>I need to print tickets (receipts) on a star SP200.
>Should I use report designer or use low level commands, How do I specify the variable page length or how do I use the fopen() "?", "??" commands

You could add a Printer in the Printers Control Panel, then use ??? to output lines to that printer.

#DEFINE VFP_CRLF CHR(13) + CHR(10)
set printer to name (lcPrinter) && receipt printer name in Control panel
??? 'output line here' + VFP_CRLF
...
??? 'last output line' + VFP_CRLF
set printer to default