You don't need spend a lot, I have three Wansview ones from ebay have run continuously almost two years now.
Most of them are more or less Foscam clones.
The supplied software and documentation is often poor but there's plenty of online help to be found for setting up.

One thing to watch for is that you typically want a wide angle lens when looking at something big close up!
You'd want 4mm or wider. At the cheaper end, sellers are often clueless and have pasted in random and often conflicting information about field of view etc.