The fact is, there are a LOT of good tents for less than $300, as most tent makers know that people will start balking if the price tag drifts much above that. Honestly, I'm not sure myself what the absolute BEST tent in that price range would be, but I can give you my top-three shortlist. Here goes.
Marmot Equinox ($259; six pounds, 11 ounces; www.marmot.com): This tent would be my winner if it weighed ten to 12 ounces less. It's still a great tent, with lots of room for two (40 square feet). Adding to its spacious feel is the fact you have two doorson either side of the front end of the tent. That allows each occupant to leave the tent without disturbing the other, and also creates individual vestibules. There's even an extra "doggie" door at the very bow of the tent. Lots of mesh for ventilation, but an extremely sturdy design sheds bad weather like a turtle.
Sierra Designs Meteor Light ($249; six pounds, ten ounces; www.sierradesigns.com): Identical in size to the Equinox, with a single big door and vestibule on one side. Maybe the classic freestanding two-person tent; vertical sidewalls and lots of mesh create an airy, roomy interior. Take the fly off in good weather for some stargazing.
Mountain Hardwear Light Wedge 2 ($225; five pounds, ten ounces; www.mountainhardwear.com). Not only does this tent cost less than the other two, it's also less weightyless than three pounds per hiker. The tradeoff is that it has less floor space (35 square feet) and a little less headroom. Still, it sleeps two comfortably, and has both plenty of mesh and a wind- and rain-shedding design. A can't-miss tent.
So, there's three to choose from, all for under $300. Any one will serve you well.