It's nearly impossible to make a sheet on roll20 without Pro. ;-( You'll need to be Pro and the creator of the game in order to access the custom sheet editor page (html, css, translation, preview). You could get Pro temporarily while you create a sheet. AFAIK, any game that uses the custom sheet code will remain even if the creator of the game is no longer Pro... Also once the sheet is available on github, all other Pro users will be able to manually install that code for their custom games even if you no longer have a Pro account. If it's a popular game, it may even become part of the regular character sheet templates available to all subscribers. Before sheet's were introduced on roll20, everyone had to manually create attributes and macros. While not as user-friendly, that is still an option.