If you are looking to get started in grip training at home, there are many affordable (or even free) options.
Most people will start with hand grippers, even though they are not so effective for developing grip strength for other things you might need, as they quite specific. However, if you are just getting started in grip training you can just buy one for like 20-30 bucks and start with them.
If you happen to have weight plates at your home or go to a gym on a regular basis, there is an excellent exercise which will help you develop grip strength. For pinch grip, just take two weight plates and grip them with your fingers. You can also go for a one-handed version of this exercise, which will help you increase your fingertip and thumbs strength.
Another great grip strength exercise with these plates are curls for developing wrist, fingers and thumbs strength.
A couple of bodyweight exercises like hanging from a bar (with or without a tower) or fingertips pushups can also be used by beginners in grip training.
You can also use fat gripz on dumbbells or barbells to perform various exercises which will aid you in developing fingers strength.
There are many other things you can do and these are just some examples you can use to get even more ideas for grip strength training.