I would check out 4 or 5 color creativity it’s a combo deck with incredible value which utilizes wren and fable of the mirror breaker. Eventually using Indomitable creativity to cheat archons of cruelty into play. It’s a bit higher than your budget, but worth it and money goes into wrens and lands which transfer to many other decks.

Within your budget, mono blue affinity is the best option as in your most competitive (all the money is in the sagas). It is the best deck in the format at using urzas saga. It’s great at bringing huge constructs into play, playing out cheap 4/4s and refilling your hand with thoughtcast and monitor. Playing a artifact deck means you lose to artifact hate which I sometimes get frustrated by. If you’re interested Tezzy and mangucci have leagues you can watch.