I've been stuck as a regional FO for about 4 years now with a Commercial certificate. I was thinking about using ATP to receive an ATP certificate but wasn't sure if it's worth it. Any insights?

The job postings I've looked at say ATP so I wasn't sure if I'm selling myself short holding the Commercial.

$2,500 for 10 hours in a Seminole and an ATP.

$5,000 for a B-737 type and ATP. IMO probably worth the incremental $2,500 to have a jet type AND the ATP.

Presumably he's getting the ATP so he can apply for some jobs without waiting to upgrade.

The 73 type is really only useful at SWA, and they won't look at him without 1500-ish TPIC. If he's flying an RJ (probably is after 4 years) he already knows how to fly a jet.

Yes this is to apply to some current companies that are hiring without any TPIC. Does ATP do a good job? Should I wait for my upgrade and get it for free (could be a long time at this rate)?

local fbo, fly a twin for 3 hours, get a dpe. prob 2500 at most. and you save cost of housing.

Most of the companies which hire without TPIC will still prefer TPIC to be competitive. It might be hard to get in if you are just applying off the street without inside connections. That might change if the pilot shortage actually materializes in the next few years, but I would have a plan before you decide whether to spend the money or wait. Just filling out arlineapps is probably not going to get you anywhere, even with an ATP.