Due to some unfortunate events my dad is taking my dog to Mexico (but it's going to live at our house and it'll have a LOT more room to run around in + I can still see it often) buuut my parents are letting me get a new dog, at least.
I don't remember much about how we chose our current dog (cuz I was 4 and I think my parents chose her because she was cheap >__< ) but she's a lab/golden retriever mix but she's pretty small, 20 inches or less. So I don't know how accurate that is...
Anyway, the point is that I'm really unfamiliar with dog breeds... So can anyone recommend a small to small-ish dog that is also relatively calm (or lazy. it'll be indoors most of the time and I don't really like jumpy dogs). Also, it can't be too expensive since I don't care about having a purebred dog or anything from a breeders, so recommending a mix is welcome too.

(but i am fond of pugs <3 i guess their noses are bad for the weather though)
Aaaand another thing -- is getting a dog from a shelter okay if I'm not completely sure what makes a healthy dog? because we adopted one when I was really small and I remember it being really sick and us having to take it back

i don't really want that to happen again...
edit: I live in Texas so a dog that can stand the heat is necessary. And I can probably take the dog on walks regularly and let it run outside so excersize isn't a problem (but again, no hyper dogs)
edit edit: Forgot the most important part -- I have allergies, but they've mostly subsided... I don't want to risk it though so I'd like a dog with shorter hair and is there such a thing as a hypoallergenic dog?