Hi Kathy,
it depends on how much skill you want to develop.
For the start, I would recommend getting a 50mm prime lens. There are loads and loads of them out there and they can be had for real cheap. As said, I had the Miranda 50mm f2.0 which I picked up for £10 in an antique shop. You might be able to get hold of a Pentax A50/1.7 or a Pentax A50/2.0 for a good price, too. They will give you a few more options with regard to automatisation. However, note that none of these lenses offer zoom and they require manual focus. However, they will help you learn photography much better because of this and they offer beautiful pictures in lower light and beautiful creamy backgrounds. The latter can make finding the right focus point quite difficult as well.
Later on, I would recommend buying a 28mm or a 35mm lens and maybe an something in the range of 70-135mm. The former will be nice for wide angle landscapes and the latter will be good for portraits.
However, if you want to play safe you may want to consider buying a zoom lens. Something like the Pentax FA 35-70 or the the FA 28-70. I can also recommend the Sigma 28-105 UC-II.
You may also want to
check out the review sections and look at sample images. Since flea markets and car boot sales are never predictable, this is probably the best resource available.
Good luck!