How Much Does a Smile Makeover Cost?

Not only can the cost vary but the treatment can vary as well.  A smile makeover can be as simple as whitening and recontouring which can be under a thousand dollars to placing porcelain on every tooth to a new bite which can be over $50,000.

Variables for makeover costs can include:

Experience and training of the dentist
Materials used
Lab used (if used at all)
Number of teeth treated

Not all dentists are trained in smile makeovers, some even approach it as "fake it 'til you make it" for smile design. That CAN work for some people, but the more critical consumer wants more.
Plastic veneers would cost less than porcelain, but won't last as long. The lab used for porcelain veneers will affect fees as well, as some labs are "adequate" and others are more talented.
Some smile makeovers just need a few teeth treated, but more commonly, 8-10 teeth are involved.
Yet, some "makeovers" simply need enamel contouring.
Some makeovers can be a few hundred dollars, and others can cost closer to $12,000 to $15,000.

In cosmetic dentistry, most often you get what you pay for. Meaning that if you pay very little, you may not be happy with the results/may get a less than ideal result. A smile makeover can mean many different things, and it's important to consult with you dentist to find out exactly what he or she recommends to meet your expectations. Often times, I will have a patient bring a photo of what they want their smile to look like and compare photos of their current smile to it and talk about what treatments they may need to get a smile close to their expectations. Some patients need very little modification to get what they're looking for while other patients may need ortho (braces), gum procedures, crowns, etc. This is where you dentist can help explain exactly what YOU will need. 
Just a side note, I do not recommend the "snap on smile" as a long term smile makeover option. I've seen patients pay for it and were happy with it for a few weeks, maybe months but then it either broke, discolored, or wouldn't fit and they were unable to use it moving forward. Composite veneers (aka composite bonding) is also a good option that can be more affordable than getting porcelain veneers or crowns. But with composite veneers, you want to make sure find a dentist that is skilled in performing this procedure with lots of experience.

The "most bang for you buck" will be just white fillings, but fillings won't last long and are not long term solution.  I'd say on average budge about $25,000 for a complete smile makeover.  It may be less, it may be more depending on what you present the dentist with.

Difficult question to answer.  The overall cost will depend on what exactly is necessary to complete the makeover.  Generally >$2000 per tooth for veneers.  Keep in mind that all makeovers are unique and you should consult with a cosmetic dentist for a more accurate number since there are many other factors involved.