Pavers would be okay if they are level, and have an adequate base. If your pavers are not level, you'd probably have to remove them, and redo the base, and reinstall.
If your electric bid includes all components and labor, it's really not that bad. A GFI breaker and panel will cost well over $100 alone. Then there is the cost of the permit, wire, conduit, connectors, etc. It adds up quickly.
Consider yourself lucky. The last person I spoke to had to have his service upgraded to 200 amps(it was either 60 or 100 to begin with), and he spent close to $1500 by the time his electrician hooked up the spa.
Brewman