Every year teams shell out big money to sign their top Draft picks and international targets, in turn placing significant price tags on what they hope to be bright and productive futures in Major League Baseball. However, a look at MLB Pipeline's recently released 2018 Top 100 Prospects list offers an immediate reminder that a prospect's signing bonus is far from an indicator of success.
Of course there are plenty of early-round Draft picks (including 43 first-rounders) and big-dollar international signings (White Sox outfielder Luis Robert got a $26 million bonus) on the list, but there are also those who were selected much later in the Draft or signed for a low six-figure bonus.
Perhaps there's no better example of this on this year's Top 100 than Ronald Acuna, the new No. 2 overall prospect.
:: Complete 2018 Top Prospects coverage ::
Signed by Atlanta out of Venezuela at age 16 for just $100,000 in July 2014, Acuna flashed immense physical tools at the outset of his career, but was beset by injuries in '16, in what was supposed to be his first full season. As a result, Acuna, in spite of his undeniable upside, failed to crack the preseason Top 100 list.
Fully healthy in 2017, Acuna's prospect stock exploded as he tore through three full-season levels, finishing the year in Triple-A. The then-19-year-old ultimately batted .325/.374/.522 with 21 home runs, 60 extra-base hits and 44 stolen bases to garner MLB Pipeline Hitter of the Year honors, and he continued to impress in the offseason as he was named the Arizona Fall League's Most Valuable Player.
With Acuna on the cusp of the Major Leagues and looking more and more like an absolute steal from the international ranks, here's a look at others from the humblest of beginnings.
Victor Robles, OF, Nationals (No. 6 prospect)
Unlike Acuna, Robles has been a fixture in MLB Pipeline's Top 100 list for several years. With plus hitting ability as well as elite speed and defense in center field, Robles made the jump from Double-A to the Major Leagues last September at age 20. He ultimately earned a spot on Washington's postseason roster, capping a remarkable climb through the Minors after signing for $225,000 out of the Dominican Republic in July 2013.

Francisco Mejia, C, Indians (No. 11)
Mejia firmly established himself as a can't-miss prospect when he tailored a 50-game hitting streak across two levels in 2016, four years after the Indians had signed the Dominican native for $350,000. The switch-hitting backstop also made the jump from Double-A to the Majors last September and should continue to challenge Indians incumbents for at-bats in 2018.
Sixto Sanchez (No. 26) and Adonis Medina (No. 86), RHP, Phillies
The Phillies' international efforts produced a pair of Top 100 Prospects this year in right-handers Sanchez and Medina, who signed for a combined $105,000. Sanchez, a 19-year-old right-hander with electric stuff who's coming off of a breakout full-season debut in which he reached the Class A Advanced Florida State League, signed for just $35,000 in February 2015, while the Phillies inked Medina, 21, for $70,000 back in '14.

Estevan Florial, OF, Yankees (No. 44)
Florial was set to receive a seven-figure payday from the Yankees until MLB discovered a discrepancy in his birth certificate and then barred him from signing for one year. The Yankees ultimately got their guy at a significantly reduced cost, signing Florial for $200,000 in March 2015. The 20-year-old outfielder already looks like a bargain, as he showed the best all-around tools in New York's deep system during an impressive full-season debut, across two levels, in 2017.

More international notables: No. 52 Keibert Ruiz, C, Dodgers ($140,000 signing bonus in 2014); No. 68 Fernando Romero, RHP, Twins ($250,000 in '11); No. 74 Albert Abreu, RHP, Yankees ($185,000 by Astros in '13).
In terms of Draft picks, this year's Top 100 Prospects list features 43 former first-round selections, nine second-rounders and five players taken either in a supplemental or Competitive Balance Round. Beyond that, the group includes five former third-round picks, a trio of fourth-rounders and five players selected in the fifth round or later.
Willie Calhoun, OF, Rangers (No. 53 prospect)
Calhoun paced all junior-college players with 31 homers at Yavapai (Ariz.) in 2015, the same year he signed with the Dodgers for $347,500 after they selected him in the fourth round. While a lack of across-the-board tools did hurt his Draft stock, Calhoun has shown that his potent bat was well worth the low-cost gamble. The 23-year-old belted 31 Minor League home runs last season and added one more in the Majors as a September callup after joining the Rangers in the Yu Darvish trade.

Jake Bauers, 1B/OF, Rays (No. 64)
A seventh-round pick of the Padres in 2013 who signed for $240,000, Bauers immediately showed advanced hitting ability upon launching his career, so much so that the Rays acquired him in the William Myers trade the following offseason. That pure hitting ability -- he's slashed .276/.362/.412 in five pro seasons -- continues to be the 22-year-old's calling card and should have him firmly in the mix for first-base reps in Tampa in 2018.
Corbin Burnes (No. 69) and Brandon Woodruff (No. 96), RHP, Brewers
Despite their focus on adding high-ceiling, impactful positional players at the top of recent Drafts, the Brewers have found repeated success in targeting undervalued college hurlers in later rounds. The club's selections and subsequent signings of Burnes (fourth round, 2016; $536,400) and Woodruff (11th round, '14, $100,000) are testimony to that. The latter completed his surge through the Minors last season en route to logging six big league starts, and Burnes appears hot on his trail after a dominant first full season in which he reached Double-A.

Chance Adams, RHP, Yankees (No. 75)
A starter for just one of his three seasons at Dallas Baptist, Adams showed enough upside for the Yankees to give him $330,000 as a fifth-round pick in 2015. Moved into the starting rotation the following year, the 23-year-old righty has posted a 28-6 record with a 2.40 ERA and 279 strikeouts in 277 2/3 innings since the start of 2016. He led the Triple-A International League in opponents' average (.197) last season after topping the entire Minors (.169) the year before.

Tyler Mahle, RHP, Reds (No. 84)
Mahle has blown past all expectations during his ascent through Cincinnati's system since signing for $250,000 as a seventh-round pick in 2013. The 23-year-old right-hander was especially dominant in 2017, when he led the organization in ERA and WHIP before holding his own over four big league starts.
More Draft notables: No. 23 Austin Hays, OF, Orioles (third round in 2016, $665,800 signing bonus); No. 73 Jon Duplantier, RHP, D-backs (third round in '16, $686,600); No. 94 Tyler O'Neill, OF, Cardinals (third round in '13 by Seattle, $650,000).