Where are you based? What territory? In the EU, the distance selling directive means that customers of online orders are entitled to a full refund with 7 days of purchase even if they have just changed their mind.
I've never invoked that law, but presume it would apply to software.
Apple offers this benefit globally IIRC - but they hide the UI as deep as they can and force you to go through a rather manual customer support process. Clearly it's not meant for people to actually use.
I've never invoked that law, but presume it would apply to software.