Squid along with any other type of fish or meat can give you food poisoning if it is not properly prepared or cleaned. You can also get food poisoning from squid that has gone bad over time, so you will need to make sure that you store it properly. If you are not going to be using the squid that you get from the supermarket, it will be incredibly important to make sure that you put it in the freezer so it will keep for as long as possible.
If you are going to be using the squid relatively soon after getting it from the store, you can feel free to put it in the refrigerator. Just make sure that you do not leave your squid out at room temperature as it can go bad very easily this way.