This discussion is one that comes up quite often so there’s lots of ideas, a few linked below.
What it comes down to is how you heal is entirely up to your character - quite alot do go the saw bones method with or without fake blood and leeches, but there is nothing against realigning auras, concussive phrenology (bashing people’s heads) enthusiastic sermonising or even just telling the body to behave itself and act proper, as long as you do it with conviction so how much paraphernalia you need is up to you.
For the saw bones option:
The cheapest healing tool options are a ripped old (charity shop) sheet for bandages and something needle like or tool like to poke people (with their consent). Clay sculpting tools are recommended for not being pointy enough to hurt your patient or more importantly you!
The cheapest potion / herb options I’ve used is the contents of a tea bag in a twist of muslin. Food safe, bin when it gets wet / muddy / splits and replace!
After that the sky is your limit, but yes if the contents are not food safe please superglue the lids on, Larpers get a bit too into the roleplay and are liable to try stuff even if you told them it wasn’t food / skin safe 5 minutes earlier.