A lot of health stores sell liver cleansing and colon cleaning regiments. Is there a cheaper way of detoxifying?

No need. You don't need to detoxify your body. Your body is designed to get rid of toxins. Companies that sell you detoxifying products are only after your money.
Water +fiber. What ever you do dont buy a detox product. Your liver and kidneys do an excellent job of clearing most toxins . If you are constipated take a fiber product like psyllium. U just need to be well hydrated (drink water). There are some real toxins like heavy metals (lead) etc which may not come out and you should see your md if those are an issue. Detox products are just a scam to take your $$.