Should i pay Cash or Check?

There is no records of cash transaction. Get a bank cheque cost only 10dollars from the bank you withdrawal from. On the safe side say i.e I buy a car privately from person A 4k cash he denies it and I didn't get him to write some sort of receipt now I have no car or cash. If he got a 4k cheque he can denie it but the evidence shows he received 4k from a bank cheque from my bank account now I can get to charge him with fraud or larceny.