Well I'll see if I can make a list of the tools I have in my box that I'd use on the car besides a welder and some metal. My tools are mainly name brand like Mac and Snap-On but I know Craftsman has a decent line up for an at home DIYer.
First off, a small 90* air grinder (most of my tools are air) with a 2" pad and a box of 36 grit greem 3M roloc discs.
This is the one I have
and here's the discs and fitting
Works good for taking it down to bare metal AND giving it a good surface for some mud (aka Bondo) to stick to. Also nice to give you some fresh metal to weld to.
Second, you'll want to get a orbital sander
. I spent $140 for mine off of ebay and that was for a nice one, cheaper ones can be had for less obviously. There is also two main types of pads that hold the sandpaper onto them as well; sticky and velcro. Typically, the sticky pad will come with the sander so then you can go buy a roll of paper, slap some on and go.
Next, a slide hammer. My recommendation is to get a stud puller, not a regular slide hammer where you have to drill holes into the body for it to screw into. I've seen them at Harbor Freight for around $150 or so, mine I got from Snap-On and ran me a little over $500 for the kit. This will include the gun (like a hand held spot welder), a couple boxes of studs, the special slide hammer that claps onto the stud and typically destructions on how to use it. Its pretty simple to use, slide a stud into the tip of the gun, put it up to the bare metal inside the dent (since you used your grinder to make it bare), push the tip into the gun, pull the trigger and release just as soon as it clicks. You'd need to play around with it because if you hold it too long, it'll actually weld deep into the metal and when you cut the stud off, it'll leave a hole in the metal.
A set of hammers and dollies. Another thing that can be had at Harbor Freight or Sears. Since you're not going into the prefession, I'd go to either of these two places to get them. Pretty straight forward too so I won't go into much detail.
Next, is kind of obvious. Mud, Bondo, filler, whatever you want to call it. Go get some but make sure you get two different ones; base (which is more coarse and harder to get smooth) and glaze (used over the top of the "main" filler to make it smooth and give it a nice finish to primer over). Some cheap plastic spreaders do the job. I know Wal-Mart sells them:lol:
Then you'll want some sanding blocks. 3M sells a good variety of them and with blocks, you don't want to go too cheap since this is what gives you a better, waveless look. I have a 3", 5" 8" and a 12", all in the Hookit (3M's name for the velcro system) style. You'll also want to get a soft block that is a half circle, I refer to them as a "taco pad" since you take a round disc, the same you'd use on a orbital sander, and wrap it around it.
Now there's probably a bit more that I'm probably forgetting but these tools will be the ones you'd use the most. I did a full body resto on a '69 Mustang, spend 6 months working on it, my first bodywork project, and came out flawless. I had no prior body experience except for the ocassional "DIY in the driveway half @ss dent fill job/beat it out with a hammer" sort of deal.