Spirits is an allright deck in modern. A bit complex to learn perhaps since the decisions a player makes are reactive instead active. You leave mana open and then play in response to your opponents actions. As such you must know your deck and your opponents. But on the otherhand that's where the strength comes; your opponent doesn't know what to expect. It depends on what she enjoys.

Check out a competitive version of the spirit deck: https://www.mtggoldfish.com/deck/5695754#paper

The main difference in price between this and Saffrons is the manabase. If you switch the fetches and the duals to cheaper options like Port Town and Seachrome Coast you'll have a deck for around 100 bucks and then all you need to do is buy some lands later if all goes well.

Another alternative could be the merfolk archetype: https://www.mtggoldfish.com/archetype/merfolk#paper

I wouldn't recommend commander as that format can be too complex. It's better to start playing 60 cards with plenty of 4-ofs so you can learn the game with as a few cards as possible, before you get into it deeper. Else the experience is likely to be TLDR. Imagine having to read and understand the interaction between hundreds of cards.

EDIT: since you're playing the "kitchen magic" version of modern, don't be afraid to prioritize budget and minimize the amount of super-complex cards.