Not sure how long it will take for this to show up, as I've been banished to needing posts approved (for what I have no idea), even though I've been on various iterations of this place since 2002...So I apologize if my comments are duplicative.
My father was in the biz and I've done numerous reno's in most properties I've owned.
1. Pick 1 brand for the majority of your battery powered tools so you don't have 3-4 different chargers and 1 battery for each. Biggest hassle is a dead battery with no replacement on the charger, or having to swap batteries because you are using 3 tools and only 1 battery.
Make sure you also pick the same voltage for the tools. Tools started out with 12v, then 14v, then 18...Now 40V or 80v are common. Higher the voltage the better. Many brands have tools at multiple levels
2. HD or Lowes usually have bundles at a discount you can buy with multiple batteries and the basics for tools. I would recommend drill, reciprocating saw, circular saw as a minimum. If you are doing a lot of framing/drywall work, get an impact driver...much lighter and efficient than a drill for this purpose.
3. Lowes bought the Craftsman line from Sears..not sure if quality/warranty is the same, but I would suggest a name brand for things like wrenches or sockets...they are much better and should last you a lifetime. I've cheaped out for them at the vacation house....it's a mistake imo
4. You can get non electric tools like hammers, wrenches, pliers etc really cheap at swap meets or flea markets. When we had an estate sale, tools was one of the first thing people wanted, so go early if someone is advertising tools. I wouldn't buy any battery powered tool at a swap or flea.
5.After the basics, buy tools as you need them, but don't be hesitant to buy a specialty tool if you are doing a job that recommends it. You'll have the tool for life and it will often make the job 10x easier. Plus by doing it yourself, the cost of the tool, even if it's pricey, is much less than paying a pro. Sometimes, the chance to get the tool was the impetus for me to tackle a job..lol
6. Help you buddies with their home projects and they will help you. When my group were new homeowners, we helped each other. It was a great way to help a friend but also catch up. And spouses couldn't get upset because you were a good Samaritan. And there is always time for a few cocktail after the work is done.
My own .02....don't drink if you are using power tools...especially table saw or router...a simple slip could lead to serious injury.
Good luck...enjoy the process. Sweat is a great way to build equity