Prices at beauty colleges should be minimal, and your person will be under supervision. You should be very directive about how you want the job done. I haven't been to our local college yet, but one of my friends goes regularly because she can't reach her feet.
Regarding the podiatrists doing nails: they are paying attention for complications of diabetes and other conditions with poor circulation and neuropathy. People with these problems can so easily lose a foot, and then a leg, due to an unnoticed sore becoming gangrenous.
I remember trying to explain this to my own mother, but she refused to give over her outrage at a medical doctor coming to the senior center to cut toenails and charge the government for that service. In her mind it was just wrong. But she was frail and had the horny toenails of old age, so she should have just gone with the program instead of contorting her arthritic body to do it herself. I try to learn from her example, shall we say.
If you want to try mineral oil, remember that old fashioned baby oil is just scented mineral oil. Look for a sturdy set of straight across toenail clippers to do the job. The ones I have are good for me, but the ones my dad used to have looked like they belonged in his toolbox they were so rugged.
Best of luck.