Whenever you are about to buy a lifetime deal there are several key things to do first:
First, look closely at the pricing tables of the lifetime deal compared to the retail pricing. Depending on who is offering the lifetime deal, the benefits could be limited compared to the full retail version. An example of this is an email marketing tool that might have a limit of 1,000 subscribers for the lifetime deal, which would be terrible compared to free options like MailChimp who offer 2,000 subscribers.
Another thing you want to look at are reviews of current clients and people who have just bought the lifetime deal. Don’t even think about pressing buy now before reading these reviews as it will give you a good idea of whether this app is a dud or winner.
While you are looking at reviews, also try to find the product road map. This will give you an idea of how committed the app maker is to the project and whether their vision matches your requirements for the future.