While there's nothing "wrong" with in-app purchases, they have gotten a little out of control these days and more often than not, free-to-play games riddled with them become more "pay-to-win" than anything else. We can't really fault developers for using them, after all it's easier to get people to install a free game than a paid one, and bills need to be paid no matter how you cut it. Still, not everyone wants to have to deal with them and nor should they. Honest Android Games is a simple website that simply lists games that don't have any in-app purchases in them and it clearly tells you what and why you'll be paying for.
It's a nifty website and it's extremely easy to use. While the Google Play Store does in fact tell you that games and apps feature IAPs, it's not all that clear and a lot of people would miss it completely. Here though, you can simply download apps and games that don't feature any sort of IAPs. It's also a great way of discovering games that you might not otherwise have heard of. Honest Android Games is a curated effort so, you're definitely going to find different games than you would from a simple browse in the Play Store.
Ultimately, the fact that you'll discover different games that you might not otherwise is perhaps a bigger deal than the fact that this tells you the games are free of IAPs. In the end though, this mostly comes down to personal preference. I'm a sucker for endless runner games, which often tend to be IAP money banks, however some games tend to take things a little too far and could quite easily be a full game for an upfront cost. Let us know in the comments how you feel about IAPs and whether or not you're happy to put your money into a game.