Pleco add-ons are available both through our own online store and through Android Market's in-app billing system. See this page from the instruction manual for details on how to purchase with each method.
In-app billing is the easiest way to buy Pleco add-ons, since it automatically bills your Google account, but it requires your device to be configured in a way that's compatible with Android Market purchasing (so you may have to swap your SIM card or install Market Enabler, and it may not work at all on non-Google-approved-devices), and you can potentially lose access to your purchases if Google decides to block your account. Also, 30% of the cost of your purchase will go to your cell phone carrier and/or Google, rather than to Pleco and the editors and publishers that develop the wonderful dictionaries we license.
Our own store is slightly harder to use than Android Market, since you have to enter your billing info again (though we do accept PayPal), but all of the money aside from payment processing fees (generally about 3% of the purchase price) goes to Pleco and our partners. And it works regardless of what type of SIM card you have or how your device is configured - even OK on a totally non-Google-friendly device like a Kindle Fire.
If you lose or replace your device with another device running Android, you can easily transfer over your Pleco add-on purchases without buying them again. If you bought Pleco through Android Market, tap on the "Restore Market Purchases" button at the bottom of the "Add-ons" screen to reactivate your software; otherwise, tap on "Manage Registration" at the top of the Pleco "Settings" screen and enter your Registration ID. (you can retrieve it from My Orders if needed).
This same procedure applies for activating Pleco on additional Android devices for yourself or other people in your household as well; you are permitted to install it on up to three of them at the same time for copies of Pleco purchased originally on iOS or Android, but only on one device for copies purchased originally on Palm OS or Windows Mobile.
You can be confident that any product you buy from us will be supported for years to come; we've been in business since 2000 and we won't be going away anytime soon.
Our official upgrade policy is that all software updates within the current major version (2.1, 2.2, 2.3, etc) are offered free of charge, and that major version upgrades (3.0, 4.0, 5.0) may or may not be free.
To date, we've never charged a fee for a version upgrade; we have customers who bought our software back in 2001 and are still using the latest version ten years later without ever having had to pay an upgrade fee. What we prefer to do instead is to release the basic software upgrade for free but charge extra for some new features (particularly those that require us to pay royalties or license fees).
We offer lifetime free e-mail technical support with all purchases; just contact us and we'll be delighted to help you.
We do not currently offer telephone support; we're not big enough to have a dedicated 24-hour line, and if we offered telephone support during business hours it wouldn't do much good for the plurality of our customers who live outside the US, so we've decided it's best to forego telephone support altogether for now at least. We're very quick to answer emails, though; most messages are responded to within half a day, many within a few hours, and we don't stop answering email on weekends.