You can check iherb and other retailers and see what epa only products they have. I know some high EPA products, like Barlean's Ultra EPA, which only has a small amount of DHA. If looking for EPA only, I recall Minami had a 500mg EPA, and a teensy (negligible amount) of DHA. But Minami stuff is way pricier than it should be.
And ethyl esters were about way before Lovaza hit the market. That is why most people felt Lovaza was a waste of money. Fish oil, OTC or not, either comes in ethyl ester or triglyceride form. The latter is closer to how it's found in nature, by the way. High concentrates, like Nordic, sort of have fake triglyceride forms (reconstituted). It may not matter much really, although I seem to recall most depression studies used the ethyl ester forms. If looking for best absorption, triglyceride is probably better.
If your pharmacy is giving you a problem with getting Vascepa, it could either be an insurance issue, or your doctor didn't mark that little DAW (dispense as written) box. And the pharmacy may be trying to cheap out by looking for some sort of generic. If that is the case, easiest solution is just have your doctor rewrite the prescription. If your insurance doesn't cover it though, OTC will be way more affordable.