Live audio guy here, and I can say that custom-moulded plugs truly are tremendously above anything you can get in a universal fit. I got mine done for about $100 USD and they are super comfortable. If you are able to save up for it, I cannot recommend enough that you get custom ear plugs.
I also own a pair of Etymotic ER20XS universal fit ear plugs and they really irritate my ears. It hurts to wear them for a long period of time, whilst the custom plugs I can wear for hours at a time. Your mileage may vary, depending on the size and shape of your ear canal, but for me, universal fit ear plugs are just really painful. Whenever I forget my customs, I just go with foam ear plugs because I just can’t stand the Etymotics.
None of that is to mention how much more balanced the sound is with custom ear plugs, I find that universal ones just don’t sound as good.
Depending on where you go to have it done, it likely can increase the price you pay to have them done. If you’re crafty enough with an at-home mould you could likely pull it off, but I know very little about those, do they come with an acoustic filter? Depending on how the DIY customs turn out, they might not sound as good as a universal fit. Edit: looking online, Decibullz DIY custom ear plugs look the most promising. Their “High Fidelity” model appears on Amazon and comes with three different acoustic filters, attenuating at 14, 17, and 19 dB from lowest to highest. If I was gonna try an at-home custom, these are the ones I would go for.
I was fortunate enough to have gotten my customs when I was part of a live production group in college where we had it in our budget to get executive board members custom-made ear plugs. We had an audiology center right on campus with a doctor that could take the mould and send it to the company that would make the plugs, at no extra cost to the student.
I’m actually looking into some universal plugs right now because I might have written off universal plugs entirely due to the Etymotic’s triple-flange shape being such deep insertion. This weekend I’m expecting a few pairs of universal fits to come in the mail, I’ll follow up with how they work out soon! :)