Great question - I'd explore your options. If you have a local co-op or organic store, ask them for options. Your local Farmer's Market may have grass=fed beef where it's much cheaper. Check with a meat locker as well to see if they have any grass fed options. Visit http://eatwild.com and see if that helps as well.
I'm with Paleotron - eating regular beef and supplementing with omega 3's does nothing to diminish the offset of omega-6's you're already getting. Stats suggest the normal SAD has a 30:1 ratio of omega6/omega 3's. Way off kilter which impacts inflammation and many conditions/syndromes.
Is it worth it? I think the answer is yes. Look at your healthcare costs. IF they are higher than normal, then you have your answer in that scenario as well. Let's hope they aren't too high, but you get what I'm saying.
IF grass-fed is still not an option - everyone else has said what I'd also recommend - low fat cuts since the toxins animals ingest go to the fat areas.