Good day Mrs Meyer, Based on your request for the cheapest cockroach gel, I would recommend either the Roach Expert Cockroach Killing Gel (5G) for R78, or the 5G Indoor And Outdoor Roach Expert Cockroach Gel 4-PACK for R116. Both are from a leading brand and offer great value and treatment area for their prices. To use the gel, simply place small amounts in areas where you see cockroaches often, like under appliances or in cabinets. The gel works by attracting and killing the cockroaches slowly as they feed on it. Reapply every 3 months or if you see roaches returning. Please let me know if you need any other details. I'm still learning, so I apologize if I'm missing other offers in my search results. Wishing you all the best getting rid of those pesky roaches!
Here are some details on the gel amounts: The Roach Expert Cockroach Killing Gel that is available for R78 comes in a 5g tube. With a few small drops in various spots, this should be enough to treat cupboards and smaller areas. The Multifunctional Roach Expert Cockroach Killing Gel 3 Pack available for R179 contains 3 tubes that are slightly larger at 7g each, so you get a total of 21g with this option. This multi-pack will likely provide enough gel to easily cover all the areas you mentioned behind appliances and in cupboards around your kitchen. The larger amount per tube also means re-application likely won't be needed as frequently. Both options come with safe, easy-to-use gel baits that roaches will consume and take back to their hiding spots, eliminating them from the areas you need treated. Let me know if you need any other details!