I work at a mechanic shop. In general,

• spark plugs and coils/ignition packs
• battery
• any and all air filters
• oil change

Can all be done in your home driveway for under $100 and half an hour of free education from YouTube for 95% of all cars. They're all dumb easy, your least favorite coworker could do it. Depending on your level of expertise you can also add brakes to this list, but incorrectly installed brakes will kill you and will be expensive if they don't, so lots of folks leave those to the professionals. But if the shop recommends you any of the above you tell them no thank you and then you pick up the parts from AutoZone for 1/5 of the quoted price.

Special shoutout to batteries though, if you're driving a Rich People Car (essentially anything as or more expensive than a Benz) lots of them will fucking demolish your battery if you don't take it to the dealer service center to get the system reset with new battery voltage. Whole check system is frankly unnecessary and could be easily done automatically even if you did want it to happen, but no. They all want to ride the battery at the razor's edge of available voltage so that if you dare install one outside the dealer service center it'll last about six months before death, possibly catastrophic death. But if you're driving a Honda? No problem. You can remove the battery while the car is running and it'll just keep chugging along.

I hate to break the news to you that way, but I think you wasted some money. That said though, if one of those failed, the others might follow suit soon. Now you're prepared with the knowledge that you can fix it yourself for way cheaper if that does happen.