Staff note: This post may contain affiliate links, which means Pentax Forums may earn a small commission if a visitor clicks through and makes a purchase. If you would like to support the forum directly, you may also make a donation here.
I have nothing new to offer besides the good advice you have received, just reinforcement. Make sure the weight rating of the tripod and the head is well more than your heaviest camera/lens combination that you will use with it. Make sure it's as tall as you want. I would recommend an arca swiss type quick release system. If it doesn't look sturdy, it probably isn't. Like krazykat, one doesn't do it all for me, I have a large heavy Induro, a MeFoto Backpacker tripod, and an even smaller MeFoto Daytrip that I can use as a tabletop or to get really low, and I also have an even smaller thing called a Pedco UltraPod II that can fit into a large coat pocket. There are a lot of good tripods made by many different manufacturers. If you have a chance to get to a store and see them do so. You should be able to get something new in your price range, especially if you can find a closeout. If you buy used make sure you can test it out. Hopefully you can avoid the pitfall most of us made when we bought a cheap tripod that didn't turn out well. I can't complain much, I only spent $7 on that first cheap one. If you don't already have one, get a wireless remote to use with the tripod, the cheap ones on ebay work just fine. Good luck with your purchase, it's one accessory that can really improve your photography.