Individual gift tax free person to person $10,000/year, but

whether their cash comes legally is a seperate issue regardless how you deposit it. Assuming they can always prove the cash from a clean way (such as withdrawl from a bank etc.) make sure you keep a record how two of them gift the money to you and your spouse ($40,000) so you don't need to pay any tax on the gift. -- Check IRS website to see whether they've raised that limit recently otherwise you have to split the rest to the next tax year unless you want to pay gift tax.