In my case, "solo" includes my 80-lb. dog. I want him to have a bug-free space, too, which sort of eliminates tarps (although I'm going to do some backyard trials with an Equinox 8×10 tarp and making my own bug net)–tarp, bug net and groundsheet for the two of us is pretty much the same weight as my current tent.
My current shelter, which I really like, doesn't quite fit the category of "best bang for the buck," but I really like it! It's a Gossamer Gear/Tarptent Squall Classic. It's the 2009 version which has a zippered vestibule (I am not fond of velcro–especially since it tends to get full of dog hair!). It pitches really taut with a nice taut bathtub floor. I know it's supposed to be a 2-person tent, but, IMHO, it's too small for two adults (unless they really like being spooned together). It is, however, exactly the right size for my dog and me.
I used the Six Moon Designs Lunar Solo for a couple of summers, but it's a bit too snug for both the dog and me. For just sleeping, it's fine, but when the dog and I were confined to the tent by bad weather it was rather claustrophobic. I also encountered a lot more condensation in the LS than I have in other silnylon tents, even when solo without the dog. I also had troubles with my head hitting the tent wall over my head when I sat up, even though I'm only 5'3". It did hold up really well in Colorado thunderstorms and Wind River winds, though!
If I were advising a beginner on a low budget what to get for a solo shelter, I'd suggest a tarp (maybe an Equinox silnylon tarp from Campmor) or the Tarptent Contrail.