Small green house (Rivervale)

I would like if possible just a idea. A small shade house or something like that with a door on it. So I can connect it to my back door so my feline friend can enjoy the outside.feel quilty her not going out but been a few years not going out side. She would get hurt. Anyway thought I'd ask. Don't have alot if money as on DSP. Just thought I'd ask. Take care.