Need advice on replacing tires and inner tubes
please forgive me as i didnt know where else to post and im a TOTAL novice when it comes to bikes.
we are currently on a roadtrip from Houston back to Los Angeles, my parents live in houston and gave me and my wife their old bikes, Cypress DX giants, men and women. since they have ridden in them for over 5-7 years, the tires and tubing is bad i believe. Air will not fill in the tires. We are in dallas for the weekend and tried several places to replace the tires/tubing but all are on backorder. As we drive back to LA, i am thinking about my options in LA as our budget is small, and i want to look for the most affordable manner.
i see that the tires are 700x40c. what are my cheapest options to get the job done? (i have 4 tires , 2 bikes)
1. should i buy tires and tubing online and just find a bike person in LA to replace for me?
2. or should i look for a cheap place in LA to do everything, maybe dicks sporting goods? what are some other affordable places?
3. what is the estimate in price i should be targeting to replace 2 tires on a bike? along with tubing?
im not sure if anything else needs to be done, friends have said possibly a tune up as well?
i live in West LA by the way