New to me bike! Looking for suggestions.

I just got this Kent 700C for $70.
It needs new tires and definitely a tune up. What are some suggestions for a beginner looking to tune it up? Should I pay for the service or should I learn how to do it myself.
I’m wondering what type and price point is recommended for tires. Something for someone who is just starting off not trying to break the bank. It’s for casual cruising use until I decide I want to use it for traveling to run quick errands. Any advice is much appreciated! 🚲