Offering flat pricing including shipping seemed to make sense for this type of purchase. I checked the prices of similar food subscription packages and kept that in mind - they seem to range from $17 to $33 typically.
I put together several candy packs at different weights and settled on 250g, 500g and 1kg - I priced them up and worked out a per gram price point so when I'm looking at new products I can work out if it's good value. Eg. x pence per gram of candy.
I put together a chart of shipping prices. Listing 3 different world zones (EU, US/CAN, AUS/NZ) and delivery speeds (surface/airmail/48hour). That enabled me to put a flat price on shipping. So for example I use the AUS/NZ price as standard, if people order from other locations then I save on postage.
I'll probably make some pricing adjustments over time, as orders grow I should be able to improve margin by buying larger packs, once I get around 10 orders per day that brings down shipping costs too, I can pass that value on to the customers. I'm looking forward to getting the new site launched! Thanks for your feedback!