Chains are worth the small expense. Chains are also of real benefit with worn or non-aggressive tread tires. I usually carry chains whenever I do any off-road or long distance driving in snow. I carry a set for both the car and the 4x4 van.
Most vehicles can use chains on the rear if there is about an inch of clearance all around the tire.
Oversize tires might limit this so watch for it. Front wheel drives are a bit more fussy about what chains to use. See the warning about using tire chains only on the front and the strong oversteer it can cause. Buy the right sized chains for your tires, links can be added or cut off but it is better not to have to. They tend to be a bit smoother and have more traction.