If it was me just starting out, I would look at buying the basic tools you'll need like a drill, 1/4" impact and grinder. What nobody has mentioned is this: there are tons of 18V Ni-Cad Dewalt tools on Craigslist that people are selling real cheap, because they bought the 20V stuff. Some of the 18V stuff is damn near new and unused and can be had for $20-$30.
Now here is the kicker, you can buy an adapter, charger, and 2 20V batteries that works in these tools, and you can then use like new tools with new performance from the upgraded batteries. Here is a link:
https://www.amazon.com/dp/B016K1UEPS/?tag=atomicindus08-20
But I would only buy the basics like a drill and impact along with the adapter kit.
Here is the best part of going this route. You can then upgrade to the new 20V platform over time by buying the bare tools only, instead of buying a kit since you'll already have the batteries and charger. Then as you slowly upgrade you can sell off the 18V stuff you bought in the 1st place.
This is how I did it, and the new batteries with the adapter has made a huge improvement in the 18V tools I own and the run better now than they did new with the Ni-Cad batteries.