A bit over that budget, and tough to find, but this mech with 306 atty drip tank is under 4" without the teflon extension. All you'll ever need though, and when you decide to give up vaping, you'll get all your money back and then some. It rides comfortable in the CHANGE pocket of my jeans. If you're looking for pocket friendly, rba and compact are mutually exclusive except for things like the Octopus and Igo-L. Beautiful, it has in spades.