It won't be as budget-friendly because of this, but it still is somewhat cheap if you want it to be.
Not to mention that alot of Geo characters benefit alot from the defence stat, a stat almost nobody else wants so they can use artefacts that other characters would consider trash.
If you want a Budget build, you can take Xian Ling, Bennette, Geo traveller and Noelle.
You can swap in other Geo characters like Zhongli or Albedo if you have them, it's pretty flexible at the end of the day.
it's optional and it's ok to get with a more standard pyro set like Crimson Witch of Flames and/or Gladiator.
But If you have it already or can for it, you can run Retracing Bolide on Xiang Ling/ Diluc who is your main DPS.
Slap on a +0 Petra set on one or both of the Geo characters that can easily make rock shields ( so basically anybody but Noelle... she CAN keep 100 % uptime on shields on her own, but its a pain IMO )
The other one can also run a full +0 Petra, or you can run a full Noblesse ( or 2 from both for more burst damage if you have somebody like Zhongli or Albedo )
Geo Traveler can do both, but I prefer to have him as a pure damage buffer, so I prefer to run a full Noblesse set on him and leave the shields to my other Geo character( Zhongli is 1 of my 2 5-stars ).
The benefits of this build depends heavily on who you actually put into it ( gee, who could have guessed that ? )
So here is a short list of a few benefits of the different Geo characters:
Geo Traveler: cheapest character to build in the game thanks to "free" constellations and ascension materials.
He also has a crit buff on his ultimate ability that is not to be underestimated and can do somewhat decent burst damage if you can afford to upgrade his artefacts on him.
Noelle: also F2p friendly because you can always get her, she offers to heal if for some reason your shield breaks a lot and you are too lazy to get NRE and fill it with food.
She has an instant panic button with her shield ability and being a claymore user she breaks rocks pretty easily, but most Geo characters can do that so it's a minor benefit at beast...
you run her for her availability and her healing most of the time.
Ningguang: She has the second-best burst damage of everybody if you can afford to upgrade her gear, she also is able to block projectiles making you even harder to kill.
She may lack the glorious back muscle Noelles has, but she is still pretty good Waifu material and could break rocks with those killer legs of hers.
She is an unstoppable juggernaut, but offers little benefit for anybody who isn't Geo outside of crazy high burst damage output as survivability should not be a problem with 2 Geo characters.
Zhongli: THE BEST geo burst damage support ( Ningguang would beat him as main DPS, but that's for another team comp)
He also offers easy access to a panic button like Noelle, and his ultimate does tons of damage even with low-level artefacts and can crowd control almost everything.
If you run him with Geo traveller you can also make a few meme combos to make dicks out of his and the traveller's ability or create some somewhat decent damage over time thanks to Geo resonance.
Being a 5 star though, I don´t expect most people to get access to any of his constellations that actually matters ( the low-level once suck IMO )
so you run him for his damage and CC.
Albedo: Albedo has a little of everything...He got good burst, can offer extra damage thanks to his field ability.
( And he can make you fly if you are into that
Childe and hillicurls hates you when you go more then 2 feet up in the air ( watch the video, its pretty fun and educational if you don´t use Geo traveller alot )
He gives less survivability than most other Geo characters because he doesn't have much in defensive abilities but makes up for it in other ways.
He gives 125 elemental mastery for 10 seconds every time he uses his ultimate elemental burst, and because of how cheap and can be used ASAP most of the time even with only 12 seconds CD.
Not to mention his C1 if you can get it makes him generate crazy amounts of energy particles,
so you run him for the extra damage, elemental mastery and the energy regeneration he offers.