I would most defiantly spay your girl. Here is a good article explaining the benefits.
How Will Spaying Change My Dog? | ASPCA
Make sure you pick a Vet that is experienced in small dog spay’s. Ask if they have a Vet Tech monitoring while the Vet is performing the spay- make sure you get pre op blood work done.
$800 is a lot of money- I never heard of a spay in that amount.
Here is a link to help you find “low cost spays”
Low-Cost Spay/Neuter Programs | ASPCA