No, but there is a level in Loopy Landscapes that gives you unlimited money, you just need to stay above a park rating of 700.

I can't remember what it's called but it's early in the list so I don't think you'll need to unlock it.

Someone posted this link in another thread, can't recall who, I grabbed it from the FAQ thread:

Flatland save with 3,000,000 in the bank

It's right at the bottom.

Great! I'll try that.

Thanks everyone

RCT 1 has an sandbox game after you complete all of the missions Called Mega Park. RCT never received a sandbox until RCT2 which contains licensed levels based on Six Flags Properties.