My answer to "Where to practice?'' is: anywhere. My fiance and I have danced at clubs, bars, outdoor festivals, back yards, living rooms, parades, restaurant lobbies, on sidewalks, parking lots, fields...if there's a bare patch of floor or ground, we'll dance on it. (Appropriate footwear advised).
It's impossible not to dance, in my opinion, if there's good music playing. (Especially live).
I have even been known to practice by myself while pushing the grocery cart.
If you don't have a regular partner, see if there are people at your studio who'd like to get together outside of class and practice.
It should not be necessary to spend lots of money (if any) to practice.
I've noticed some people at my studio don't do any dancing outside the studio. I think this is a gigantic mistake. Mainly, because they're missing out on a lot of fun. And they're emptying their wallet in order to practice.
Do you live in or near a large city? Where I live, there are a number of clubs and bars with music, live and recorded, where people go to dance. It isn't necessary to go with a partner - people dance with each other. You might have to ask around to find out where places are in your area, and what are the nice places and what aren't, but I hope there are some good places you could go. In my area, there are especially several places to dance Lindy, EC swing, WC swing, salsa, tango and ballroom. Most of these have no cover or a nominal cover of $5 or $10 for the evening. I'm made I don't know how many friends going to these places.
Good luck to you.