So ive had to go shopping for a new queen size over the week and stumbled into a mattress firm, looked at a few beds and really enjoyed the serta i series hybrid mattresses. problem is it was a little more then I was wanting to spend as im trying to stay around 1200-1300. im all fine with ordering online if somebody has reviews of a better bed with that price range in mind but i have no idea where to look. all i know is i need a medium/firm bed once broke in and its got to be able to stay cool, and of course last more then 5 years. is anyone able to help? back and side sleeper mainly.