Q: Greetings..had this terrible noise when I would start my 07 Hyundai Sante fe.. got a new battery and starter..but was told I need

Greetings..had this terrible noise when I would start my 07 Hyundai Sante fe.. got a new battery and starter..problem seemed to be solved..but was told that I would likely need to go to dealership to get new ignition switch and had to go to dealer because they key would need to fit. Had hoped to delay this until the end of the month...after three days...the ignition drained the starter and my car stopped...its back in the shop and the guy is replacing the starter at no cost.. I understand it requires more work..and needs a new ignition switch...My concern is that the dealer will cost me two arms and three legs..I saw that a switch can cost as little as 17 and as much as $30.. my question.. can a switch be purchased that goes under the part of the key entrance or do I need to go to dealer and have a new key programmed for the switch.? Also..what can I expect to spend at the dealership? Any other advise would be helpful.. thank you for your time.

My car has 180000 miles.
My car has an automatic transmission.