they were going to lie and told them I had experience
Doesn't sound like it's
just the pay they're trying to screw you out of. If the agency lies, and the agency-user finds out you have no experience, they MIGHT take it out on the agency, but the agency will not fess up that they were the ones that lied, they'll say "oh we didn't know, SHE told us....."
Not to mention the fact that they were going to lie says buckets about their work ethic.