I started to work on this in 2007. You could only pick 4 items from the pay menu, each had its own price.
So lets rewrite the script! We are going to create a new LSL Script and add a on_rez event to reset the when you rez the bot out of inventory. You should a script that looks like the following:
[code lang="lsl2"] default { state_entry() { llSay(0, "Hello, Avatar!"); } touch_start(integer total_number) { llSay(0, "Touched."); } on_rez(integer start_param) { llResetScript(); } } [/code]