How to have different prices based on selected quantity for the product

I want to know if this is possible.

I want to create a form that generates quotes for customers. 

People will need to be able to select a quantity (from 1-300) and then select a design, all of which are different prices. So 1 design might be £1 whereas another design might be £2.

The issue is that the designs are different prices for different quantities (the more you buy the cheaper it costs) 

Is this possible?

If I understand you correctly, you would like to sell products / designs on your forms. You will have a different price per product, and per the selected amount.

For example, if user selects only 1 item named "Design 1", the would pay $10. If they selected 100 items named "Design 1", they would not be paying $10x100=$1000, but would instead have a bulk offer such as only $799 for 100 items.

If that is what you are describing, yes, this is very much possible with our forms. You can set up your products / designs as product options on a payment form:

https://www.jotform.com/help/165-Setting-Up-Your-First-Order-Form

After you have your products set up, you can simply enable special pricing, and then set the special price for when users are selecting a "bulk" amount:

https://www.jotform.com/help/265-What-is-Special-Pricing

If you need further assistance, or if you were looking for something else instead, please let us know and we will be happy to help out.