When it comes to post-rotation decks you have plenty of options, but when it comes to decks without Lele there isn't much. I would say you have the ability to use almost every deck you want in the meta if you can get at least 1 Lele, but going without a single one is tough. Here are my thoughts on possible decks and the ones you have chosen:
Gardevoir- You said you didn't want to spend above $60 on Pokémon in your deck, and that simply isn't posssile with Gardevoir. Not only was it an expensive card before worlds, but then after it won worlds the price rose and that's a trend I believe will continue. Also, Gardevoir will run anywhere from 1-3 Lele, so that creates more problems.
Golisopod- Unless you are planning on building a true Golisopod budget deck, it also runs anywhere from 1-3 Tapu Lele. The Pokémon themselves are also very expensive, because Golisopod is going for about $8 and Zoroark is going for around $10. That being said this is an extremely competitive deck that has a lot of potential post rotation, you are simply gonna have to "pay to play".
Darkrai- All competitive Darkrai decks do indeed run Lele, simple as that. Darkrai is a remotely expensive deck for Pokémon as Drakrai costs about $6 each. On the note of how competitive it is, I don't see it having much potential post rotation. Not only does it's biggest opponents Garbodor become more powerful, but all turbo decks in general suffer from the loss of VS Seeker. I'm not expert on the deck because I have never played it, so I might be wrong.
Alolan Muk- I have heard very people talk about this deck post rotation, so naturally I know very little about it. My best guess would be it costs about an average price, and will be a tier 3 deck next rotation.
Honestly, I would recommend you look into Greninja BREAK as deck to run post-rotation. It appears to fit all your requirments, and I personally love playing it! That being said, in order to play a lot of the decks you want, you are going to have to raise your budget. Good luck!
