How can one convert elemental sulfur and NaOH or NaCl into sodium bisulfate, sodium bisulfite, sodium sulfate, or sodium sulfite? Or from one sulfur salt into another? And how would one figure out this sort of thing for any two salts?
I recently purchased Espoma brand "garden sulfur" from the hardware store (2.26kg for $6.99); the bag lists "Sulfur (S) ... 90%" as its guaranteed analysis. How could this be purified for use in preparations calling for elemental sulfur?
Making sulfite from the sulfur can indeed be done by burning and passing the gaseous results through a solution of NaOH. You'll however get impure Na2SO3, because burning of sulfur yields mainly SO2, but there also is quite some SO3, visible as a white thin smoke, when sulfur is burned.
But if you really want Na2SO3, NaHSO4 and Na2S2O5, why not order these from one of the raw photo chemical suppliers? These are really cheap chems (just a few $ per pound).
If you want to purify the sulfur, then you need to know the other ingredients. If these ingredients are water-soluble salts, then you can add the sulfur to water, shake well and then take the sulfur and let it dry (sulfur is absolutely insoluble in water). But if you want more advice, then try to obtain more insight in the other ingredients of this "garden sulfur".