We have a digital gift card product in our woocommerce that allows customer to pick from one of 4 defined amounts ($10, $25, $50, $100) or a custom amount.
Is there a way to create an item in the catalog that has the ability for one of the options to be dynamic price?
Catalog objects allow you to set the pricing_type to either
FIXED_PRICING or VARIABLE_PRICING. If its set to VARIABLE_PRICING you’ll pass in the amount that you want to charge the customer for that sale. 
is VARIABLE_PRICING only something that can be set via API? or is it in the square POS too? (I didn’t see it there…)
Variable pricing can be set in the POS as well. If you don’t add an amount when creating the item it will be a variable priced item when you save it.
Hi , Can I set min - max value for the Variable Pricing ? Thank you.
At this time there isn’t a min max setting for variable priced items.