If you're not very cost-conscious, you can get excellent instant coffee (e.g. Sightglass), but it'll cost you >$2.50/cup, much more than equivalent quality beans.
Yet another instance of fast/cheap/good, pick two.
Yet another instance of fast/cheap/good, pick two.
Right now I'm using Mount Hagen, which is a decent compromise on price/quality: it takes most of the bitter edge off compared to something like Folgers.
As a side note, instant coffee is an excellent way to make something coffee flavored, like in baking. I've even used it in small quantities to get a deeper, richer flavor in pumpernickel bread... I don't know how real bakeries do it, but it's the only way I've come close in taste to what a bakery produces.
I'll have to try Mount Hagen for a change of pace sometime, though.