“What is the cheapest way to replace a missing tooth?”

This is a very difficult question to answer as there are many factors that affect the decision process. First, one has to determine if they are eligible for the numerous way of replacing a missing tooth. For example, if there are teeth on both sides of the missing one, a fixed "bridge" may be possible. Or, if there is adequate bone and space, a dental implant may be possible to replace the missing tooth. Furthermore, sometimes the "cheapest" option now, is not the cheapest option in the long run. Sometimes an individual may opt for a removable partial denture to replace missing teeth, only to end up not wanting something that comes in and out and paying more later on for a more permanent solution. This is where I urge you to discuss all your viable options with your dentist. Perhaps the dental implant, which will cost more in the short-term, is your best option for the long-term, which may in fact end up being the "cheapest" overall.

When replacing teeth, removable solutions cost far less compared to fixed or "non-removable" solutions. A single-tooth denture, or "flipper", can typically be made for $200 - $400. This denture is functional and you can eat with it in place. Another alternative costs about $100 and is called an "Esthetic Essix". This is a clear plastic retainer that anchors on all your teeth in the dental arch where you've lost your tooth. The lost tooth is "filled in" on the Essix to give the appearance that your tooth is still in place. Importantly, you must take this kind of appliance out when eating as it can break easily.

The cheapest way is with what they call a flipper. They look nice but it is not recommended to eat with them, and you need to remove them when you go to bed.

The cheepest way to replace a missing tooth is to have a partial made. The partial can be either metal based or plastic based.

The cheapest way to replace a missing tooth is with a flipper, which is a temporary solution.

There are many ways to replace a missing tooth.
You asked about the most economical replacement. That being said sometimes a flipper or an acrylic tooth on a retainer can be used to mask a gap in your smile. These usually run a couple hundred dollars depending on the number of teeth included and if any wire clasps will be needed to hold it in placed.
The next option might be a type of bridge. This could range from bonded type bridge to a full coverage bridge. With this option teeth next to the missing tooth would be prepared, an impression taken and a lab (either sent out or in the office) would fabricate a prosthesis that would be attached to the remaining teeth to fill the space.
Another way to fill the missing space would be a dental implant. While this may not seem economical up front over the years of service it provides it may become a very economical option. With this choice a titanium post is inserted into the jaw bone to replace the lost tooth root. After some healing time a crown can be attached to this implant to replace the missing tooth. A very predictable and long term solution.

A removable type of appliance

A transitional partial made of acrylic. AKA a "flipper"

Get a removable acrylic plate that has a missing tooth attached. That would be the cheapest way to replace a missing tooth.

With regards, thanks

Dr. Narkhede

Place a removable tooth in place until you are ready for something more costly

No treatment at all is the cheapest. If you’d like a replacement tooth, a bridge or implant or partial denture are usually the options. A fiber bridge might be the cheapest option but not the most durable and it’s not always a good option. An implant often times ends up the most expensive on the front end but lasts the longest so the price balances out in the long run.