When you are looking at casino games to play especially from places that give a free offer, the first choice would be progressives if they allow. The reason behind this and please check with the terms per casino is that you can at some of them keep your winnings on jackpots. Whereas other games you are limited on what you can keep with many set at less than a hundred.
Playing free sites which give fun credits to play with you want to be sure they do not install some sort of software on your device. It is a common tactic that game developers do. Casino games cost money to develop so they always have some sort of purpose to make money. Whether it is from having users buy extra credits, serving ads directly or some sneaky install of software. On apps if you notice they are very large that should be a warning sign as any legit app should be quick and not real large. If you notice your device acting up or running hot then you may have installed unwanted software along with your casino games. The worst part is that even if you uninstall it might be to late and they have already attached it to other files. Playing at legit sites is always best way to go to protect you from the problems you can face with free apps. If the casino has a fun mode then it would safely work without the concerns as above and you can play the games freely without the worries.
If and when you decide to play real online casinos and you want to purchase, know that they use encryption to keep all your information safe. If you still worry about trusting this you can always use a third party web wallet to purchase through. Each casino has a list of all options that are available, just view the banking section to see what your choices are. If you have problems with purchasing credits to play on the casino games just contact support and they can guide you through ways to fund the account.