Aww, poor fish. This makes me want to get creative to accommodate the needs and comfort of the fish, and to make the friend happy.
Unfortunately she would still need more than one tank. Tropical fish and goldfish don't belong together, because they have different needs. I've seen it done, but it makes me cringe.
Around here I can usually find a plain 10gal glass tank for about $10 at Walmart, or the local chain pet shop. (fine for a betta, a little cramped for an adult goldfish)
The want ads in the newspaper; people are always getting rid of fish tanks for cheap or sometimes free.
Likewise Craig's list, second hand stores, and goodwill.
A container pond can be made out of just about anything that holds water, from a plastic storage bin to a kiddy pool. And they hold a lot more than 10gal.
My indoor/outdoor goldfish have an 80 gal galvanized stock tank that they share with the kid's turtle. (Obviously not an option in your friend's case, but just an example)
An upside down file crate and a few clean rocks make a handy island. It's very utilitarian, but can easily be spruced up with the addition of live plants. (I kill houseplants, so my fish are stuck with utilitarian.)
As with any housing you will put living things in, rinse it very well first. No soap- ever.
At the very least, if she can't afford a filter, I would add an air pump. That and regular water changes are the most crucial.
Even on a shoe string budget, a proper container and a bit of imagination could make something that totally blows away those darn little bowls the pet stores sell (but shouldn't
).
Hope your friend is able to keep her fish and make them comfortable.