I always say no because receipts have been shown to commonly contain BPA and other cancer-causing/endocrine-disrupting chemicals that can be absorbed through your skin. The data seems to be mixed on whether or not the dermal uptake is significant enough to pose a threat, but I just don’t want to take the chance.
If you have to have a receipt, try to touch it for the least amount of time possible, avoid touching the printed side, and keep it in a container or Ziploc bag in your main bag or somewhere else.
https://www.snopes.com/fact-check/receipt-paper-harmful/
https://www.ecocenter.org/our-work/healthy-stuff-lab/reports/receipt-deceit-toxic-chemicals-receipt-paper/test-results
https://www.sciencedirect.com/science/article/pii/S0160412020319863
https://pubmed.ncbi.nlm.nih.gov/33313651/
https://ehp.niehs.nih.gov/doi/10.1289/isee.2013.S-2-37-02
I would guess that the exposure to BPAs from handling receipt paper for a few seconds would be incredibly minimal, especially when compared to other potential sources of BPAs like food and drink packaging etc.
Maybe don’t reuse receipts as paper towels or toilet paper, but briefly handling them enough to put in a wallet etc is probably safe in the grand scheme of things.
