Bluebear is a tier 4, generally people either give those away or sell them very cheap :c 200-300 is usually about what tier 1's sell for, theres a great list on these forums of the usual popularity of every villager, it comes in handy quite a lot for me and many others here :] http://www.belltreeforums.com/showthread.php?109343-List-of-Villagers-Based-on-Popularity
It's sort of an online currency specifically for these forums :3 You can earn it by simply posting a lot, or selling things that people will trade their tbt (also called "btb") for. Many users here prefer it to in-game-bells because it's quicker to exchange, and also in a way more versatile (when you're buying forum-based things like collectibles, avatar animations, etc.)
You can check how much you have under your avatar where it says "bells"
I'll buy her for 250 (not for me but for someone else), is it okay with you to hold her until tomorrow (or some earlier time if they tell me otherwise )?