If I were you, I'd take out black and go monogreen. The potential of either not getting a black mana, or drawing an opening hand with only a black mana isn't worth the benefit. It also makes Primal Bellow worse. Forced Adaptation , too, is pretty slow- if you're looking for a quick kill, a single counter per turn isn't really what you want. Try Vines of Vastwood - it's a pump spell and a "counter" for their removal.

Yea, I'd seen vines of vast wood before, I'd how i missed that one. I dont know, I have the forced adaptation, guess I just threw that in cause it was right in front of me. That's for reminding me of that, I'll switch it up for sure. What creature should I put in for the Plague Stinger though? I'd like some evasion.

You could either go blue for Blighted Agent , or play Apostle's Blessing as a form of evasion- give your creature protection from their blocker, and you can swing right through.

Trying to avoid bant infect, it's too common. I'd do selesnya for that Apostle's Blessing , and as nice as Blighted Agent is, I dont know if I'd want it. I play for fun, not to win, so even if bant is the best, it's not really what I'm going for. Doing selesnya, I guess I could also throw in some Spirit Mantle and kinda do an infect rendition of a selesnya hexproof. Though that would mean the deck wouldn't really be all that budget.

Most Infect decks will run Apostle's Blessing and when the decks are sonic they run Blighted Agent instead of Blight Mamba

How does that look? I also added Become Immense, I know that's beng played right now too. I wasn't sure what to drop, so I went for the Primal Bellow, Blessings of Nature and some Giant Growth. Probably going to drop 1 Apostle's Blessing for 1 more Vines of Vastwood

It's ok I guess but I have deck like this one called Dirty Needles, Mono-Green infect

Look at that for what I've found people run

If you are adding blue, take out the Apostle's Blessing for Distortion Strike. Primal Bellow is too much mana.

You may want to check your math on the price.

The Cathedral of Wars are very bad. I recommend you take it out.

I recommend you look at my infect deck. Just look at my profile. I have a blue-green infect deck, too.

I know what I could do to make this deck a hell of a lot better, but both your decks are too expensive, I want to keep this at sub 20$ on MTGO. I will be dropping the Pendelhaven and Cathedral of War for check lands (depending on their price). As for the Distortion Strike, I have no idea how I missed that one, I seriously love that card.

Ah. Well, good luck. :)