I need a SMS auto responder which will send a random number

I need a SMS auto responder which will send a random number to potential customers who text a specific word to my number. Here's my plan: 1. I post an ad that says "Text the word "bounce" to (708) 586-xxxx to get $10 to $100 off your next order". 2. When the potential customer texts the word "bounce" to my number, their number is saved in a spreadsheet with the date and time they texted (and geolocation if possible). 3. The system will send the customer a random discount between $10 and $100 with: The possibility of getting $10 off being 60% The possibility of getting $15 off being 25% The possibility of getting $20 off being 10% The possibility of getting $30 off being 3% The possibility of getting $100 off being 2% 4. Depending on the discount they won, they will get a unique discount code.