301 Redirects - Where to Host?

I have several expired domains that redirect to another domain that's more brandable and marketable.

The problem is, I have a host like WPEngine, where there are only so many slots for URLs and the hosting is going to become much more expensive with the more domains I add.

The want to keep the expired domains redirected at the .htaccess level, so my understanding is they have to be on a hosting account somewhere.

Would it be a good move to transfer the expired domains to a cheaper host (ex. hostgator), set up the .htaccess level redirect to save on costs?

Are there any better alternative solutions?

That's a perfectly normal solution. I keep my redirected domains hosted as well, moving hosting to save some money is perfectly fine.

You can get relatively decent yearly hosting for under $100, so it's not a big deal. Go for it.

If you want to host them , and at low cost then amazon offer free servers for hosting for an month .

Free - Cloudflare.