I am looking for inexpensive ways to solve a problem. My parents are not able to visit my home.

Are your parents wanting to come to your home? Or is it you that would like them to come? I ask you that b/c I have been in the same position; I wanted my dad to come to my home for Christmas one year to see the decorations and to celebrate the holiday here with us. He was feeling nervous, however, for similar reasons as you're writing about, and we have 2 steps to get into the house from either the garage or the front door. Yes, 2 people could have helped him, but his pride wouldn't have enjoyed that. Plus, I think he felt awkward having to use the toilet no matter if I DID get a riser for it, you know? So that's why I ask you the question.

I wound up going to the ALF to celebrate Christmas with the folks that year and we had a very nice time. The chef made a lovely meal and my DH and I gave the folks gifts, etc. It all turned out well and there was no stress or anxiety on anyone's part.

If it's your folks who want to come visit you at your home, you've gotten a couple of good suggestions for how to remedy that situation.

Best of luck!

I got a stand alone commode when my dad was here temporarily. inexpensive and doesn't require any permanent changes or installations.
A couple people could probably help her up the two steps if she rarely visits. Unless you're talking about two flights of steps?
Otherwise just have dad visit, or visit during outings away from your home that are accessible to both parents.

There are extensions that bolt to the toilet, or a commode can be placed above it to raise the height (or if there is a private room available the commode could be set up there). A simple grab bar or two can be screwed to the wall to make a handhold at the steps.

Well, if you can't afford the upgrades for them to visit, that's OK. You don't have to have them in your house to be a caring child. Go to them. Take them to the park. To a restaurant, etc. Maybe you could at least drive them by your house if they haven't already seen it?

If dad really really really wants to come to the house, hire a sitter for mom so he can make the visit.

Sometimes acceptance is the watch word. Why not just continue to visit them? We cannot always get what we want.