surf Adorama and you can find some decent deals on used equipment, I think I saw some 18-70s on there last I checked and even without VR id take it over the 18-55 for its longer reach and if I remember its MTFs come off cleaner, and at the long end its faster than most kit zooms
a 50mm f/1.8 is a good cheap lens thats handy for bodies with the AF motor, which you have, but IMO its too restrictive as you one and only lens, if it was a Full Frame or film, then I wouldnt mind a 50, thats actually how I learned, on an old Pentax with a 50mm 1.7, but on a crop sensor, its just simply not wide enough, an the AF-S 35mm is a step in a better direction on that front, but IMO still not wide enough for an only lens
heres a link for it, get a zoom, youll thank me later, the 18-70 is a great choice, it was the kit lens on the D70, the step up from your D50 back in its day
Lenses