i want to save as much money as i can
Then it is best, as wrk101 says, to start with a complete bicycle, rather than start buying individual parts for a bare frame build! That is the absolute most costly way to go, unless you already have the parts. Also, he is bang on the money about offending offers. Most people will entertain up to 25%, below asking price. Any more (or less, to be more precise) and you risk offending the seller.