Assuming you only use RBs on 1 and 3 stars feats: 10x200=2000 RBs Assuming you only use RBs on 2 stars feats: 12x200=2400 RBs but considering there are feats that are earned automatically upon tutorial skip/too easy to earn with organic gameplay, <2000 is probably fine. I can't remember how much 4 stars feat cost though. I believe it's 7 for a SP.
There's not an exact no. for this. A 1 star feat is 1 RB A 2 star feat is 3 RB's A 3 star feat is 5 RB's This means it could take as little as 2000 RB's but only if you're exclusively buying 1 or 3 star feats. You can also get some free feats in there. For instance, buying the 4 1 star hero combos in lvpe grants the 3 star feat for doing all the club mbos without having to buy it. The same applies for some of the emblem feats. If you have all the Lantern emblems, if you purchase the feat for collecting each individual 1, the feat for collecting them all will pop. Edit: looks like Catastrophic beat me to it.
*punch* I didn't include feat-set-bonus though. You're right about LPvE team-ups and old TC emblem sets, I'll add old seasonal feats to the list. And I just confirmed it's 7 for a SP with a 4 stars feat, even though I think that's the only one.
You are better off buying all 1 star feats and 5 start feats first. 1 star feat = 10 feat points = 1 RB 3 star feat = 25 feat points = 3 RB 5 star feat = 50 feat points = 5 RB Buying a 3 star feat you actually lose .5 RB. If you can buy feats that unlock other feats that is a bonus. LPVE and some others.
Sorry 1 2 and 3 star. Replace the 3 with 2 and 5 with 3. Mistake on my part was trying to do two things at once. But the basic logic still holds. By the one she you are not losing .5 replay badge.
I spent 3000 RBs on an alt to get them to like 378 SP. It was worth it though due to the sale. You need more than one toon in this game. One main ain't enough sadly. What sucks is you still need to get them CR afterwards.