My first router came with a box of worn-out bits, some with steel (not carbide) edges and some with solid guides instead of bearings, which I didn't know existed until I got them. They burn the wood. A lot.
I bought one of those small cheap assorted sets and it was great for getting started. Since then, I bought additional (and better quality) bits as needed. It works for me. Start small.
Here are lessons I learned late:
There are many different types of straight bits. Some of the ones with carbide sides are not suitable for plunging into wood, because they do not have a carbide cutter across the top of the bit. (I wonder if some people try plunging with them anyway, and how well that works.) You can find straight bits with thin carbide cutters on the sides and the top for plunging, but I prefer solid carbide spiral bits for those plunge cuts. The solid carbide spiral bits are not cheap, but are durable and nice to have. There are multiple types of spiral bits.
The same is true for keyhole bits and the bits for making T-track in wood. I use keyhole bits to make slots in the back of wall hangings, such as my spouse's scroll saw intarsia projects. Some come with plunge tops and built-in cutters around the shaft to make the narrow straight part above the slot. They can plunge and go. Some can't plunge and require a drill hole first. Still others require you to drill a hole AND make a slot (dado) with a straight cutter first. After that, you change the bit to cut the slot.
Pay attention to the details and do your homework.