Most shops will charge 4-6 hours for the work, depending on if an alignment is included or not. Hourly rates can vary substantially, but range from our rate of $62/hour on the low end to ~$130/hour on the high end.
That would put a spring install at $248 at the low end, without an alignment, to $780 on the very high end with an alignment.
At 4 hours of labor and an $800 total price, you are paying for a $200/hr labor rate, which is far far higher than any shop I have ever encountered. You may want to ask for the shop you're working with to clarify their hourly rate to you.