Fix vendor price while vendor is buying items

This reverts commit 19fb79656f3789ef8ce87b62c47ba3e7b277345f
Merge pull request #279 from dlowe-net/fix-vendor-buy-price

Fix vendor price while vendor is buying items
Casting money_t as lld instead of ld
Use PRId64 macro in list_commission_item()
Fix type in list_commission_item()