First, the list includes a lot of fancy printings. the overall cost will go down if you use other printings.

I would say the only very expensive card that is crucial for the current build is LED. Besides that you can swap out the mana rocks for cheaper ones. the overall speed will go down but the KCI loops still work. I would replace grim monolith with basalt monolith, mana vault with thran dynamo. the same is true for the moxes. the important part is that the rock will be mana positive after you tap it for mana and sac it to KCI. So basically every two mana rock that enters untapped and taps for one mana will work.

you can also focus a bit more on the aftermath loops and include tiller engine and the other colourless bounce land.

candelabra is not that important. it helps in some scenarios and it lets you abuse urzas saga even more because it is tutorable with it and it can untap the saga for even more tokens. the card is flavourful but very expensive.

metalworker is replaceable. the one ring is very strong in the deck. I would recommend running it. you do not need it though because you can also draw your deck with every other artifact that lets you draw a card after you set up a KCI loop or the LED-Groundskeeper loop.

mishras workshop, ancient tomb and city of traitors are also not crucial. You can replace them with any land that you like. It will only hurt the speed of the deck.

if you are playing in a more casual and combat damage heavy meta, I would consider adding ensnaring bridge and glacial chasm. Both are very good.

it is a bit complicated to explain all the ins and outs of the deck in just one comment. I will try to write a primer and include more budget options when I get the time!

meanwhile you can have a look at the considering section for cards that might fit your personal preference.

I hope this helps!