Pam Johnson-Bennett is well known and offers good information on many topics of cat care.
Her article on Litter Box Reminders is short but is worth a read whether you are buying your first litterbox or have lots of experience with cats and litterboxes.
Prices for litterboxes range from a few dollars to $200! A few online reviews recommend a simple open-top litterbox like this one, available at places like PetSmart, that has high sides but a low entry. The cost was around $20. You can also consider buying a large storage bins to use as a litterbox.
If you have kittens, you need to make sure they can scale the entrance to the litterbox. The choice, however, is yours to make and everyone has specific needs and wants.
PAM'S Litterbox Reminders
Here are some subjects covered in the article:
Besides the litterbox, obviously you also need litter. Again, prices and options vary considerably. Do your own research and/or check out some online ratings like The 10 Best Cat Litters in Canada. Ultimately you will make your own decision but it is worthwhile reading some pros and cons to the various brands.
If you do change the brand/type of litter, do it gradually.