Offer product upgrades

Hi from New Zealand

I have just two products, but about a dozen product upgrades that may be selected by the customer, or not.

For example
Product $20
Upgrade A $1
Upgrade B $5
Upgrade C $2
Upgrade D $5
Upgrade E $3
Upgrade F $5
Upgrade G $3
Upgrade H $1

The customer might choose the product and no upgrades, or upgrade A, B and G... for example. You get the picture. 

This isn't the same as colour or size variations. Is this possible, and how would I do it? Is there a plugin that will help?

Thanks in advance!

James

Hi James, Any luck here? looking to do the same!

Thanks,

Cp