This app is one of the best ways to learn english irregular verbs and it can be used as a irregular verbs handbook because of its convenient search capabilities.
All verbs are devided into suitable groups so that you can memorize not only separate verbs but whole groups of words.
It provides also 3 kinds of exercises - verb cards training, which is digital analog of common used flashcards (with cool real-life animation), writing training, in which you write Past Simple and Past Participle forms and training in which you select appropriate forms of verbs.
To make process of learning even more easy all verbs have corresponding levels of complexity so you can begin with low complexity and go to the high one. There are 3 levels of complexity in the app - low, middle and high.
The trial version doesn't have time restriction. The only restriction is that - you can't use middle and hight complexity verbs in exercises. Anyway they are available in the list of irregular verbs so you can use this app as a handbook in trial mode. You do have access to the exercises with low level verbs.
So feel free to try Irregular verbs trainer. It's good place to start studying English.