What do you mean by Smogon's recommendations are expensive? Are you talking about not having BP to get certain things? Also, do you have some sort of goal in mind for how far you want to take this team? Are you trying to get to at least 50 wins, are get as far as you can? If you're trying to get as far as you can, there are a couple things I see that would need to be changed.
- You're vulnerable to status. You don't really have a way to deal with status aside from Natural Cure Blissey, which can create some rather awkward lines. Having Substitute on your Mega Salamence can help, you can even use Substitute on Blissey. Having Substitute can help with not only dodging status but can also be useful against OHKO users that otherwise can screw this team over, such as Walrein4(It has Lax Incense with Sheer Cold, Fissure, Rest, and Sleep Talk). Substitute can also let you miss fish against moves and can be useful against Quick Claw users.
On Mega Salamence, you don't really need Defog on it. It also prefers Jolly Nature. For a mono attacking set, Mega Salamence tends to use Return over Double Edge since it doesn't make you take recoil damage, and it gets the job fine. I'd replace Double Edge with Return and Defog with Substitute. If you're fine with swapping out team members or willing to catch a Honedge(or you already have one or one of its evolved forms), you can do the tried-and-true Mega Salamence, Aegislash, and Chansey core (aka Aegimensey). If you still want to have Tapu Lele and Blissey, here are my recommendations for them:
Tapu Lele: What item do you mean by Mind Table? Also, I don't recommend running Focus Blast on Tapu Lele in the tree. Yeah, it's coverage for Steel-types, but its accuracy being 70 can eventually cost you your streak should you be in a situation where you need to land Focus Blast to win. You can use another move like Shadow Ball. You could do Hidden Power, but that depends on what Hidden Power type you have. I'd honestly recommend using a Scarf set because if Mega Salamence isn't setup, your team loses to Salamence4(Which is a Mega Salamence set with Double Edge)
On Blissey, you don't really need Stealth Rock on it. Unlike on PS where you fight actual players, the AI hardly switches out. That means Stealth Rock isn't really important to have in the Battle Tree. Usually, this role is better done by Chansey, but I'd recommend changing your Blissey set to this:
Blissey (F) @ Leftovers
Ability: Natural Cure
EVs: 4 HP / 252 Def / 252 Spe
Timid Nature
- Seismic Toss
- Substitute / Toxic
- Minimize
- Soft-Boiled
The EV spread may look weird, but the max speed lets Blissey outspeed slower Pokemon so it can setup Substitute on them. Max Defense since Blissey already has high HP and Special Defense. If you do Toxic over Substitute, then you can just do the 252 HP / 252 Def / 4 SpD spread with Bold Nature.