While purchasing MQMs is the most expensive way to reach a higher Medallion level (if you are short of qualifying), it is still an option.

This is the LINK to purchase MQMs.

You must be logged-in to see your personal pricing.  Some accounts are not eligible. (mostly accounts that would not be able to reach a Medallion level)

Of the accounts I manage, prices range from $725.00 to $1025.00 for 2,500 MQMs and $1325 to $2095.00 for 10,000 MQMs.  These purchases also count as MQDs for US residents.  A mileage run would be a much cheaper alternative; of course, that does require you take a flight.  If you can make a mini-weekend vacation run, all the  better.  Though, there are additional costs involved in such things, so purchasing MQMs might be the best option for some.  If purchasing MQMS means reaching Diamond Medallion Status, instead of maintaining Platinum Status, it might make sense because of the GUCs (Global Upgrade Certificates).  Only Diamond Medallions receive GUCs, that are applicable from almost all international fare classes.  Since you receive four GUCs, one might easily value these as much as $1,000 per upgrade certificate.  So, perhaps, spending $1000 +/- to reach Diamond Medallion and not having to take a flight before end of year could be a good value proposition for some.

Are you planning on purchasing MQMs?

Please comment, if you would like to discuss your particular situation with regard to Medallion Status and purchasing MQMs.

MQM : Medallion Qualifying Miles (the miles that establish your elite status or tier)
MQD : Medallion Qualifying Dollars (for US residents, the second requirement in addition to MQMs to achieve elite Medallion Status)
RDM : Redeemable Miles (the miles used for awards or free tickets, for example : “I need 25,000 RDMs for a free economy class ticket.”)
GUC : Global Upgrade Certificates (for Diamond Medallion members, international upgrade certificates applicable at almost all fare classes)
Mileage Run : Taking a trip for the purpose of gaining miles, often MQMs to maintain or advance an elite status level.