Here are the "Assigned Values" for the first 3 rounds just so people have a grasp of slot value. Now imagine that the Twins take Kyle Wright (RHP-Vandy) with the #1 overall pick, but they pay him a bonus of $5.77M. That is $2M under the assigned value for the 1-1 pick. That means the Twins will have an additional $2M to spend on picks 2-10, over and above their assigned value. The Twins have $14,156,800 in bonuses to spend on those 10 rounds (+ sandwich picks). Generally college seniors have little/no leverage as they can't choose to go back to school. They either sign for what they are offered or they have to play independent ball. Not many choose to go the independent ball route. (J.D. Drew, a Boras client did in '97, and a few years ago James Paxton did after he tried to return to school but was ruled ineligible by the NCAA - both were juniors, fwiw). So if those seniors sign under their assigned value it frees up cash to sign kids that may otherwise have "signability" issues. It's worth noting as well that if any player picked after the 10th round signs for a bonus of more than $100K then the amount above $100K is deducted from the team's bonus pool. ...if teams exceed their assigned bonus pool then they are subject to a variable luxury tax of 75%-100% of the amount of their overpayment.
The most bonus money given since the new CBA is $6.5M so Minnesota will definitely have some extra cash to spread around later in the draft. FWIW, only 2 players drafted #4 or later have ever even cracked $4.5M - one of them our very own Kohl Stewart a few years ago.
First Round 1. Twins: $7,770,700
2. Reds: $7,193,200
3. Padres: $6,668,100
4. Rays: $6,153,600
5. Braves: $5,707,300
6. A's: $5,303,000
7. D-backs: $5,016,300
8. Phillies: $4,780,400
9. Brewers: $4,570,000
10. Angels: $4,376,800
11. White Sox: $4,199,200
12. Pirates: $4,032,000
13. Marlins: $3,875,800
14. Royals: $3,727,600
15. Astros: $3,588,200
16. Yankees: $3,458,600
17. Mariners: $3,333,200
18. Tigers: $3,214,600
19. Giants: $3,101,700
20. Mets: $2,994,500
21. Orioles: $2,892,400
22. Blue Jays: $2,795,200
23. Dodgers: $2,702,700
24. Red Sox: $2,614,500
25. Nationals: $2,530,400
26. Rangers: $2,450,100
27. Cubs: $2,373,300
28. Blue Jays: $2,302,900
29. Rangers: $2,238,900
30. Cubs: $2,184,300
Competitive Balance Round A31. Rays: $2,134,900
32. Reds: $2,084,400
33. A's: $2,033,500
34. Brewers: $1,983,600
35. Twins: $1,935,300
36. Marlins: $1,888,800
Second Round37. Twins: $1,846,100
38. Reds: $1,802,800
39. Padres: $1,760,700
40. Rays: $1,714,500
41. Braves: $1,674,600
42. Pirates: $1,635,500
43. A's: $1,597,300
44. D-backs: $1,560,100
45. Phillies: $1,523,800
46. Brewers: $1,493,500
47. Angels: $1,459,200
48. Rockies: $1,425,400
49. White Sox: $1,392,200
50. Pirates: $1,357,300
51. Marlins: $1,326,800
52. Royals: $1,295,700
53. Astros: $1,265,500
54. Yankees: $1,236,000
55. Mariners: $1,206,900
56. Astros: $1,178,600
57. Tigers: $1,148,400
58. Giants: $1,121,300
59. Mets: $1,094,700
60. Orioles: $1,068,700
61. Blue Jays: $1,043,200
62. Dodgers: $1,018,200
63. Red Sox: $993,900
64. Indians: $969,900
65. Nationals: $946,500
66. Rangers: $926,500
67. Cubs: $901,900
Competitive Balance Round B68. D-backs: $880,100
69. Padres: $858,600
70. Rockies: $837,300
71. Indians: $816,500
72. Pirates: $804,000
73. Royals: $791,700
74. Orioles: $779,500
75. Astros: $767,400
Third Round76. Twins: $755,500
77. Reds: $743,900
78. Padres: $732,200
79. Rays: $720,600
80. Braves: $709,000
81. A's: $697,500
82. D-backs: $687,200
83. Phillies: $676,900
84. Brewers: $666,600
85. Angels: $656,300
86. Rockies: $646,100
87. White Sox: $636,500
88. Pirates: $626,600
89. Marlins: $616,800
90. Royals: $607,300
91. Astros: $597,800
92. Yankees: $588,700
93. Mariners: $579,800
94. Cardinals: $570,900
95. Tigers: $564,000
96. Giants: $558,500
97. Mets: $553,200
98. Orioles: $547,700
99. Blue Jays: $542,400
100. Dodgers: $537,100
101. Red Sox: $532,800
102. Indians: $527,600
103. Nationals: $522,300
104. Rangers: $517,100
105. Cubs: $511,900
Here is a good MLB article that explains it and has the full Team bonus pools as well.