Closing costs are the fees and prepaid items due at the closing table, separate from your down payment. In Hidalgo County, as elsewhere in Texas, they generally fall into a few buckets: lender fees, title and closing fees, prepaid items, and government recording fees.
Lender fees can include an origination fee, an appraisal fee, and a credit report fee, among others. These vary by lender, so comparing loan estimates from more than one lender is worth the effort.
Title and closing fees cover the title search, title insurance, and the closing or settlement fee itself. Title insurance protects you and your lender against certain past claims on the property, and in Texas its cost is set by the state, so it will not vary much between title companies, though who pays which portion (buyer or seller) is typically negotiated as part of the contract.
Prepaid items include things like the first year of homeowners insurance, prepaid interest, and funding the escrow account that will later pay your property taxes and insurance. Because property tax bills in Texas can be significant relative to the home price, lenders often want a healthy escrow cushion at closing.
Government recording fees are small, flat fees charged by the county to record the deed and the mortgage. Hidalgo County administers these locally, but the fee structure is standard across Texas counties.
Exact totals depend on your loan amount, your lender, the title company, and the specific transaction, so rather than quote a number that may be wrong for your situation, your lender will give you a Loan Estimate early on and a Closing Disclosure a few days before closing, both of which spell out the real figures for your purchase.