Do you have a way to make infinite mana or do you routinely have 4 to 8 extra mana per turn?

If not, I wouldn't put him in any deck.

You could play Codie, Vociferous Codex as a mono blue. He works the same but his mana ability looks more like, tap 4 colorless, add U and four colorless. Added benefit of confusing your opponents, or tricking them into thinking you mana screwed and are drawing an improbable number of islands.

Otherwise, any mono blue commander can work well without creatures as long as their strategy doesn't need then. So, no tribal (wizards), no flying centric or otherwise combat orientated. Any spellslinger commander without am ability that needs or targets your creatures would work.

I like it. Might as well include 'lose ward' or 'black and red spells you control that target x player's permanents can't be countered' since he's 7 mana.

I don't know what degenerate shenanigans your planning, but I approve.

Your best bet is probably checking out EDHREC, picking an interesting commander, and selecting the budget theme.

Otherwise, what is your preferred style of play? Do you want to beat face, control, or pillow?

How do you want to win? Self mill, mill, swinging, commander, alt?

What did you like and/or not like about Nez?

Insight is cheap and green is the most played color in commander.

Otherwise, curiosity effects, especially older ones, are cheap.

Opt effects tend to be cheap but some of the 1 mana cantrips can be expensive (~$2-3). Also, thier best with Archmage Emeritus effects (which range in price).

You could consider Trailblazer's Boots and/or Prowler's Helm. If you equip more than once, you save mana.

Cantrips like Opt are a good option, though technically not card advantage. The big ticket items would be Rhystic Study and The One Ring.

Otherwise, you could consider curiosity effects if you plan on connecting, Consecrated Sphinx, Fact or Fiction, or one of the blue creatures that draw you a card every instant or sorcery you cast.

You probably don't need it. Do your 4/5 color decks have recursion or repeatable recursion?

What makes fae good is that it has flashback itself and recursion potential as a creature. What makes it worse than the leyline or orrey is that creatures are the easiest thing to remove.

Does instant speed dramatically change your gameplay? Do you have ETBs that could be game changing if they had flash? Do you run a lot of interaction/counters that flash would help with? If not,I wouldn't bother.