I was going to assume the numbers you gave were correct, 961 548, and see if a solution could come from that, but if you assume the lowest value is $40, and Sam has to be $40, and the 9 Mugs have to be $40 (because 9 comes first in your numbers), then there is already a clear discrepancy with clue 11, which says $40 is Sam or the Mugs, so $40 can't be both Sam and the Mugs.
We know from clue #2 that $40 is Sam, so Sam can't be drinking Mugs.
If it is true that Mugs (9) has to be the first digit, then the lowest cost can't be $40, it would have to be $35 or $30 to have a chance at being valid.
So, again, presetting the 961 548 combination in the grid, and starting with $35 as the lowest value, is there a valid solution? Yes, it appears there is, going straight down through the clues when you reach the last one, the grid is filled without conflict.
9 Mugs  $35  Pippin  Stout
6 Humpens  $40  Sam  Dark Ale
1 Pitcher  $45  Frodo  Lager
5 Pints  $50  Bilbo  Porter
4 Bottles  $55  Merry  Pilsner
8 Tankards  $60  Rosie  Hefeweizer
By the way, $30 as the lowest won't work with the numbers in this order, because that would put $40 on the third row with (1 Pitcher), which we know is Frodo (clues 1 and 9), but would also have to be Sam (clue 2),
So, with the given digits in that order, there appears to be only one possible solution.
But if you didn't know the "answer" ahead of time, there are multiple solutions to the logic puzzle. I don't understand if that is the goal. You have to find all the possible solutions, and then check each location to find the geocache, but the Logic Puzzle by itself will not lead you to a single location.
