The brewpot is the biggest expense however you go, after that a bunch of plastic buckets, some plastic tubing, a bottlecapper.
If you use copper tubing to cool it down this will also cost a few dollars - not absolutely necessary but is a huge help in quickly cooling the wert. Also need an adapter for a faucet, a few tubing clamps.
You can spend a lot more (I am considering buying a turkey fryer so I can do my boil in the garage) but mostly the pot, buckets, bottlecapper. If doing extract brewing you can actually use a bunch of smaller pots and not have to boil one large one.
I did a few batches using extract syrup and a few using powdered extract, after that switched over to all grain. It doesn't take a lot of extra stuff to do all grain brewing with malted barley, especially if the local supply shop will let you grind the barley on site. Is a lot cheaper as well, at least where I live, had my cost down to 50cents/beer for 6% porter or 4-5% rye ale in 7 gallon batches.
Haven't brewed in a bunch of years though - steams up the house but good and I need to move it outside if I'm going to start back up. My current electric stove would take all day to bring my pot to a boil.