Cheapest one I know of is Cryptopia. They require .10 btc to have it added to the voting list. Then, you still have to get 250 votes and wait a few days for them to add it. Then there's Yobit who claims they'll add it in 2-3 days for .10 btc, but here lately i've been seeing a few projects pay them that and a month later still not have their coin added. I get that these coins take up server space, but they're collecting fees on every transaction. Not to mention the extra coins they make when someone withdrawals Bitcoins(some of them charge .001 fee to withdrawal). So if I were to be running one I would just remove the coins which aren't making me any money in fees and keep the rest. I guess I need to see if I can find some open source exchange and start working on it. Don't want to start from scratch.. But, that's the only way I know I can trust it.

I think coinsmarkets.com will add it for free if the dev contacts them. I have used their exchange for another coin and it seems to be legit. But they require to be in contact with the dev.