Cheap ways to prevent bug bites?

So I don't know how but a lot of mosquitos have been getting into my room (my windows are down, door usually shut). Ever since I was little, they would attack me like crazy.

I usually don't go out much but this summer I'm changing that. I feel a lot better besides all the bug bites on my legs (I don't know why, it's always been my legs they go after).

Are there any home remedies for bug bites that are easy and cheap? I really hate them and I don't want to buy anything expensive at the store if I can help it.