Offer from Texas Resources Group

Hello all.

I have received an “offer” from Texas Resources Group for a tract of land in which I hold fractional ownership. I did some limited googling which actually lead me here, and a previous post revealed that these types of rights and deed purchasers send out these offers en mass to people they find in county records documents.

I have no idea if this offer is low, fair, or high, so I do think I would like to do my due diligence and find out what my percentage of the ownership is truly worth.

If I were interested in selling my share of ownership, while trying to maximize my profit, how would one start that process? Are there companies out there who appraise ownership stakes at no cost and then offer to purchase?

I appreciate any insight or knowledge you all have to offer! Thanks!