I'm looking to do this but am on a budget.

I'm thinking either using 'Slime Baff' or Xanthan Gunge.

Any advice on what to use and how much to buy.

In my mind if using Xanthan, I have about 2.5kg of powder for a nice thick consistency. Not sure about Slime Baff though.

Thanks in advance.

Look for "Rends Slime Bath" available on Amazon.jp. Costs a bit to import but preferred the consistency to Slime Baff. I've been trying to import a lot of them but having issues.

Ive used slime baff one box (2 packets) made my bath quite thick. I would love to have used more but you gotta thin it out so it will drain. Also to me it smells like strawberry pez!

Three packs of Slime Baff will work in a half full bathtub for a fairly thick slime. Slippery as hell though, be careful. Smells like sweets and makes your skin soft though as a bonus

This was my experiment with "Slime Baff". It was good fun!

I've tried both Slime Baff and Jelli Baff, both make the water quite a bit thicker and are great to bathe in. No experience with Xanthan although i'd love to try it!

Two sachets of Slime Baff is plenty for a normal sized bath but if you want the 'slime' to be thicker you may want to try more.