We're fortunate to have a library that allows you to borrow toddler toys for two weeks at a time. That gives you a chance to see if a toy has staying power with your explorer. If your library doesn't have such a program, suggest one to them. In the meantime, work out temporary toy trades with your friends. Or watch what your child plays with when you're visiting places that have toys.
Garage sales are great for toy shopping.
You'll find playground type toys, play houses and just about anything that could show up at a kid's birthday party if you visit enough garage sales. When you're choosing your sales, look for neighborhoods with above average incomes. It's just good fishing. People who make more money spend more money on their kids. When you shop, bring your kids along.