I think what we're looking for here is a selection and quantity multiplier field that can be added in either a radio button, drop down box or multiple choice boxes.
Say that you're offering a banquet ticket to attendees at a cost of $40, but someone wants to buy 50 banquet tickets. As your form works now, you have 2 choices either a radio button or a multiple choice field that lists 1 ticket at $40, 2 tickets at $80 and so on. Now if someone wants to buy 50 tickets, the event form would have 50 lines. That's just a pain in the butt. A quick fix for that would be to allow a drop down box with added cost and auto calculation.
What we'd like to see is a one line box that says "Banquet ticket" PLUS a quantity (either a drop down 1-50, or a text area that you can input the # of tickets you'd like to buy, plus an option that automatically calculates the total cost. It would look like this:
click here for banquet ticket - ____ # of tickets at $40 per ticket = ____
Where click here activates the line, then the user is asked to input the # of tickets just before # above and the system would automatically calculate the total for that line to the right of the equal = sign.
Another example would be if your're ordering t-shirts. Do you want a mens blue, mens red, ladies blue or ladies red, the sizes are small, medium, large, x-large.
There are so many combinations that would take up so many lines, merging those options into one or 2 drop down boxes would save entry time and space.
I have a lot of situations like that. One is where we sell back issues of our journal. There are many prices, 1 price for an individual in the US, one price for individuals outside the US, and another price for Intuitions in or out of the US. ABOVE that the person or institution ordering may want to have more then 1 copy of each issue, and they may want to order multiple issues. that's not an event registration situation but I could manipulate the event registration form to allow for that if the registration options were more flexible.