I suspect it's the thrill of the chase more than the actual item that gives you pleasure. Be careful. That's a tough pattern to break because that behavior has a lot of crossover with gambling addiction. It seems fun to joke about on a forum full of tool hounds, but it has real world consequences if left unchecked (my Uncle had to file for bankruptcy and divorced his first wife because she couldn't control her purchasing habits).
Just because it's a good deal doesn't mean you need to buy it. You are not saving money by purchasing it at a discount - $100 spent is still $100 you no longer have in your account. If you flipping tools and equipment as a side hustle for some additional income, that's fine. However, you stated that have started to keep things you originally intended to sell, which conflicts with your other goal of purchasing a house.
If you really want a house, step one is setting up a budget for yourself. Step two is sticking to it, which is often easier said than done. Give yourself a little bit of fun money to play around with tools if you can, but if you are serious about getting a house, you should be setting aside a healthy portion of your excess income for a down payment.
To be clear, I'm not claiming to be perfect in this regard - I've definitely made my fair share of unnecessary purchases over the years and enjoy the hunt as much as anyone. However, it is a lot more enjoyable to make those purchases when you know you have your ducks in a row financially.