Okay, haggling over prices is not typically done in main streams establishments in the US, the price is the price and tax is not included. With that said, you may be able to haggle with a flea market vendor or a street vendor. If this is the case, you would need to speak like you have some "street cred" (credentials) so you don't get taken on a ride. Anyhow, you could use the last 2 statements, but I would drop the part where you say "if I pay cash" . This is not proper English, but you could simply say: I can get you 85, let me hold it for 85, I got 85, you sure you can't do 85 or do it for 85? , or I can only do 85. More than likely, the expectation is that you will pay cash. Hope this helps.