NEVER buy boots without trying them on. If they were from an online store with a good return policy, I'd say go for it. But don't buy boots off eBay, unless you've tried them on, you'll be stuck with them if they don't fit right.
Normally I 100% agree, but these are so cheap that if they don't fit I can flip them and probably lose $20 bucks. It's not like when she rents they go through some super fitting session other than 'what size are you' and they throw you a pair of boots that have been heat formed to fit the last person who rented them and not you for the first hour.