Buy genuine software—and the right edition.
Activation alone does not establish device limits, commercial rights or future upgrades.
Check edition, operating system and device count.
Windows and macOS, personal and commercial use, and single-device or multi-device licences may be separate products. A starting price often applies to one option only.
Know whether delivery is a licence key, an official account entitlement or a resource download. Being able to install software does not establish a genuine licence or commercial rights.
Perpetual does not always mean every future version.
A perpetual licence has to be read with its version and agreement. Future major releases, online services and unlimited devices may not be included. Subscriptions usually provide use for the paid period.
Bundled templates, courses or resources have their own rights and update terms. A licence, a download and installation help are separate things.
Match the authorisation and support to the product.
A reseller authorisation that can be checked with the developer is useful evidence. Authorisation for one product does not cover everything in a store, and a retail receipt does not establish resale rights.
Wrong editions, invalid keys, device changes, reinstalls and activation limits can have different remedies. Check edition changes, replacements and any migration or upgrade charges before paying.
Official references
Rules can change. Use the terms for your chosen product and provider.