Methyl Hydrate - cheapest form
Methyl, Ethyl, and Isopropyl are chemically similar and with the exception of Isopropyl most alcohols are just a mixture of methyl/ethyl.
For example the denatured alcohol you buy at hardware stores is 89-90% ethyl 10% methyl >1% xylene
yellow HEET is +99% methyl >1% xylene.
Everclear alcohol is 90-99% ethyl 1-10% water.
Marine stove fuel is 90% ethyl 10% methyl.
Methyl and Ethyl are so close in structure they both provide nearly identical caloric energy when burned with only a slight advantage going to Isopropyl which has slightly longer carbon chains but also causes it to soot up more when burned.
For the most part the main factor in buying stove fuels is the cost since you're basically buying the same ingredients but in different packaging.
Also, a small note on xylene. While it is considered toxic you'd have to ingest a gnarly amount of it to actually get sick and you'd get seriously sick from it long before you consumed enough of it to die. The yellow HEET has the highest amount of xylene in it but the total amount if ingested from an entire bottle would at worst cause upset stomach and the methyl alcohol would kill you long before that. It does leave an oily residue behind inside the stove itself but it's harmless and easy enough to clean up.
All that said nobody should be ingesting it for any reason, it's still bad stuff.