When to get a Phd

Well you're right that most places will list a masters and years of experience as preferred but not required - this leaves the door open for anyone with a Bachelor's to have a chance at admissions. The question to you is how would you stand out from other applicants that do have work experience and masters degrees - your application essentially needs to come to an equillibrium with those individuals so you would have to be extraordinary in GPA, GMAT, LOR's, have an amazing SOP, etc. A 3.5 GPA isn't spectacular so you can help your cause a lot by scxoring 750+ on the GMAT. Personally, absent that kind of performance, I think your best course of action is to consider a master's degree where you can get involved with research in your field. Not sure how much marketing programs value work experience. You can always apply but depending on what schools you're interested in, I'm sorry to say I don't know that your chances will be too good. Best of luck on the GMAT though!