Is HOA Estoppel necessary prior to listing?

I am listing my home for sale to see if I get any offers that I like.  If I receive an offer that I like, I will sell the home.

The home is in a HOA, and has no restrictions in selling, so I am free to sell. However, one peculiar thing is the HOA property manager is insisting that I pay for an Estoppel even prior to listing. Is this necessary and can they force me to do this? I don't see this any where in the HOA doc, and am wondering if its common practice to get an Estoppel PRIOR to getting into contract.   I fully understand, once I am in contract, I will need to pay for and get an Estoppel on behalf of the buyer.   However, I do not want to pay for something that I might not need (in case I don't receive a good enough offer and keep the home).

Any input and advice will be appreciated.