Looks solid, though I think something like Blight Mamba or Ichorclaw Myr would be better than the Thrummingbird.

Yeah I kinda agree with you on Mamba

i wouldnt count Thrummingbird out so quickly. with this being a budget having that creature with flying isnt a bad thing. considering that one of the strongest points in infect is the ink moth nexus is due greatly to it having flying. as well as its proliferate ability has better potential use that blight mambas regenerate because you would rather be spending that 2 mana on a pump spell or a blessing.

however if you are trying to go for a faster version of the deck then i do agree thrumming bird is too slow as it can only hit for 1 poison a turn. perhaps it can take up a side board slot against some of the longer more controlled games

Hinterland Harbor is a decent option here for budget.

Distortion Strike? Artful Dodge?

Both planned more as sideboard cards than mainboard

You don't think Dismember and Spell Pierce might be better SB material instead?

I would go with Ichorclaw Myr over Blight Mamba any day.

Prey's Vengeance Slaughterhorn Predator's Strike and Llanowar Augur are all decent options.

Maybe consider a Distortion Strike ?? That and Glistener Elf can do some harm.

Thrummingbird isnt a bad option. It can be used to pump up Rancor or Wild Defiance and is useful if your two infect counters awaya from winning.