Omega-3 supplement recommendations

Hello.

I am not vegan but rather a very fresh vegetarian (~3 months so far). I have aspirations to continue and reduce the amount of cruelty I am responsible for, but the actual method is still quite fresh to me.

It's my understanding that among the main nutrients vegetarians/vegans have to focus on (B12, iron, etc) DHA and EPA Omega-3s are on that list since they can only be derived from aquatic life, (as well as minimally converted from the ALA type); it is also my understanding that they, along with iron, are very important for brain health.

Anyways, does anyone have a vegan supplement they can vouch for that's cost-effective? I would hope to spend 20$ or less for a month's worth since it's just one nutrient of many I might have to look at since I'm still working this out. (To be clear, nutrition has been an issue since I was an omnivore).

Any help would be appreciated, and thank you for reading. I can expand upon anything that's not clear in the comments.