I need a companion for my Mom (82) who lost my Dad of 58 years. Any ideas?

I paid cash and had no problems but we did know the companion through another person. Whatever you decide to do i would suggest that this person go with you and mom to run errands, spend a few hours with both of you so mom gets familiar with her and she knows what mom likes. Start out with a few hours, go slowly. I would initially set it up with the understanding that it will be a trial run, nothing permanent until you see how mom relates to this caregiver.

And make sure it's the same person each time my mil didnt like when different people would show up

Does Mom want a companion is the better question? Some people don't want strangers foisted upon them just because they have become old. I surely would not want that.

It's a good idea to hire a US citizen, too. One of the private persons we called during our search, did charge very little, but only cash payments (alarm bells). Also their home was about 2 hrs drive away! So yes, do investigate & ask questions over phone / email, and there are also ways for you to get a professional -level background check done. ALSO--do a credit check. Poor credit and history of unpaid bills spells trouble.

We used people my sister knew from her church. You could also check senior citizens groups.

We used an agency, but when the aide decided to leave us, the agency didn't have anyone else in the area (remote in PA), so we went to Care. Have had two great aides through them. When you review their info, make sure to notice where they live, because we had people who were over an hour away applying, and we wanted someone within 30 minutes so they could still get there in bad weather.

I had help from dhs and commission on aging and area agency on aging

I use care website online. You put in your zip code to find companions in your area. Most are only $10-12 an hour or less by the day. You can also get volunteers from churches and other organizations. Good luck!

P.S. the agencies pay the CG $10/hr, but they charge YOU $28-30/hour.

We have had both "agency" caregivers, and "private" caregivers. These are companion CG's, not medical, just get my mom out of the house, take to beauty salon, go out to lunch, light cleaning (only!).
Our best CG has been a private hire.
Our worst CG was an agency hire.
So, despite all the glossy ads, emails, nice phone calls you might get if you contact an agency, you STILL can find really nice, safe CG on your own.
For me, it's a social justice issue: the agencies only pay their workers $10/hr, but the private ones we have paid $15-25/hour. So if you go private, you are actually paying a good wage.
Yes there is paperwork for IRS and you need to have a good umbrella insurance policy, but in our experience, the private ones are WAY better.
(Just ask yourself, who in their right mind would work for $10? desperate people...if they have any brains, they would go out and do the very same work for much higher pay and also have a say in their working arrangements).