First get the cat checked for a UTI or other issue. If the vet runs the tests and gives you a clean bill of health, you need to start by having at least 2 but preferably 3 to 4 litter boxes around with different types of litter in them. Do not just have one box with one type of litter and then change that. Cleaning the box with bleach prior to filling with litter will also help, cats are drawn to bleach, and will urinate where there is a bleach smell. Oh and do not clean up cat pee with anything that has bleach in it, that is an open invitation to come back and pee here again. I have known people to actually add a bit of bleach to the boxes and cats love it. But try a few boxes in various places around the house, avoid putting boxes in bathrooms(people like bathrooms, cats, not so much). If there is a spot the cat goes to regularly put the box there. Cats will pee/poop near where their food is, so don't bother trying to dissuade them with food there. However placing the box there can take care of the problem. See which box and which of litter they are using, make sure to have a variety,(Everclean clumping, World's best, etc), so they have different textures, some cats will go anywhere and others prefer only a certain texture. Stay away from scented litters, many cats hate them. You can add a bit of bleach to any litter to help draw them to it. Oh and if you have cleaned with a product that has bleach in it, clean that area again completely so no bleach scent remains. Oh and try various boxes. Some cats prefer open top, some closed top, some like the automatic as they won't go if there is even one pee or poop in the box. Use clumping litter as well, as many won't pee where another cat has peed, and also many, many cats will designate one box for pee and one for poop. And if only one box is available they will typically use it for poop, and pee elsewhere. Don't worry about being frugal here, you can work back to that once you find the issue and fix it. You do not have to invest a lot of money in litter boxes tho, but definitely have a few around, until you figure out the problem. It could be something as simple as not liking the texture or scent of the litter, or the litter box being in the wrong place or just not enough litter boxes available. If you try all that and they are still having an issue, head back to the vet for some blood-work, could be a kidney issue, but this method should work as long as it isn't a medical issue. If you do not want the litter box in the middle of the living room or kitchen but that is where they go, put the box there anyway for now, or nearby in a corner, and you can gradually move it later, the goal here is to get them back to using the box. Message me if you need anymore info.