Honestly, that may be a fair price, assuming these machines are profitable. Vending machines make $4-10k revenue/year. Assuming that holds for RedBox, that should make >$2k profit per year, which would make aquisition reasonable. The question is, is that what they're getting?
If I were in their shoes, I'd expand the options at the kiosks to include console games, and maybe a limited selection of snacks (e.g. popcorn), if it can be retrofitted.