Given that you haven't even decided whether you want to keep unused tokens for a future trip, this isn't something Excel can solve. Even if you don't, it may sometimes be cheaper to buy more tokens than the exact number you need. There may also be more than one solution.

Your example of 200 tokens @ $19.99 each = $119.94 is certainly not the best you can do in that instance. You could even buy 1300 tokens for less (900 @ $74.99 + 200*2 @ $19.99 = $114.97) and, if you wanted 100 tokens for something else, that might be the way to go. Alternatively, there are at least two ways of getting exactly 1200 tokens for $105.96:
900 @ $74.99 + 200 @ $19.99 + 90 @ $9.49 + 10 @ $1.49
900 @ $74.99 + 200 @ $19.99 + 50*2 @ $5.49

PS: Instead of posting links to workbooks you've loaded elsewhere, you can attach files here, so people don't have to go looking elsewhere. That gives you a better chance of getting an answer. I've replaced your link with a workbook containing the same data.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]