whatever you buy, get at least two of, that way when one needs washing you can put the clean one so you can rotate them. can find some nice things at dollar stores like baskets and stuff. if you can sew then you'll save a ton of money on hammocks
here are some things in my cage
https://www.amazon.com/gp/product/B08TZWV8HX/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B003TTY3UC/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B08ZSFD3BS/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
those are BIG baskets...fit normal sized paper, small baskets will work but these give much more room for multiple rats to snuggie
https://www.amazon.com/gp/product/B013KSVH1E/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B08RYWQ4PG/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B07W1Z3G55/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
i recommend getting a bonding scarf, i got mine on etsy. you pop them in then relax on the couch or something. it gives them a safe spot while still being on you, its whole purpose is to speed up the bonding process. if they want to chill inside it, great, if they want to explore, great too.
also my biggest advice is to figure out your cleaning schedule and stick to it like glue, keeping a strict cleaning regime will go a long way into keeping your squishy beans happy and healthy
amazon and esty both have good things though etsy is more expensive but nicer stuff. i'll link you some stuff in my cage
https://www.amazon.com/gp/product/B08RYWQ4PG/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B003TTY3UC/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B016E1QHVY/ref=ppx_yo_dt_b_asin_title_o07_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B08TZWV8HX/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B08Z7Y5168/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B08ZSFD3BS/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B013KSVH1E/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B07W1Z3G55/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
more baskets with wood ledges so they can get to the baskets. I have 3 sputnicks and 5 baskets with wood ledges from amazon so they can get to them all. i use basic dish rags in the baskets for bedding
another of my boys fave spots are these hammocks
https://www.amazon.com/gp/product/B07W1Z3G55/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1
ledges
https://www.amazon.com/gp/product/B08RYWQ4PG/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
digital thermometer. they should not be in temps above 80F for very long, its very easy for them to get heat stroke and die
https://www.amazon.com/gp/product/B01H1R0K68/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B01A1GZTKI/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0755H8BVX/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B07Q2KPDTD/ref=ppx_yo_dt_b_asin_image_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/dp/B08TZWV8HX?psc=1&ref=ppx_yo2_dt_b_product_details
https://www.amazon.com/dp/B08GL54VQH?psc=1&ref=ppx_yo2_dt_b_product_details
https://www.amazon.com/gp/product/B07W1Z3G55/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B01A1GZTKI/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
for hanging stuff
https://www.amazon.com/gp/product/B01H1R0K68/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B07KCMJTN8/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B08RYWQ4PG/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
i also have cheapo plastic baskets ziptied to the sides and use plain dish rags in those for bedding. can find some nice cheapo baskets at walmart/dollar stores
my boys especially love the sputnik to the poin that I've just ordered a third one
my deluxe came with the plastic ramps but I quickly took them out in favor of other methods but settled on wood ramp I'll link you. I found the ramps to be too steep and my boys kept munching on the ramp covers which are expensive to replace when you've got chewy butts
https://www.amazon.com/gp/product/B016E1QHVY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I also use these all over too
https://www.amazon.com/gp/product/B08RYWQ4PG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1