Monarch offer m-flex for £2.50 per flight but it's still a rip off. Read this:
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MFlex Terms and Conditions
We know that, at times, even the best laid plans change. That is why Monarch have introduced M-Flex to give you added flexibility and peace of mind when you book your scheduled flights. By choosing the M-Flex option for only £2.50 per person each way, Monarch will waive any administration fees charged for changing your booking!
For just £2.50 per passenger each way, MFlex offers you the flexibility to make a change to the travel dates or route on your booking without incurring the standard admin fee of £27.50/€34 per passenger each way. Monarch MFlex option waives your admin charges, however you will still be required to pay any fare difference between the price of your current flight and new flight should your new dates of travel be more expensive.
MFlex is valid for flight only and for date or route changes made 15 or more days prior to the departure date. One date or route change per person is permitted in each direction. For date or route changes made 14 days or less prior to departure, or for additional changes after you have used your permitted allowance, normal admin charges of £27.50/€34 per passenger each way will apply.
If you wish to purchase our MFlex option, you must do so at the time of booking. If you have chosen MFlex but do not use it on your booking, we will send you a voucher for the total amount paid for your Mflex which can be used as payment towards a future flight booking with Monarch Airlines. You will receive the voucher upon completion of your travel and will be valid for new bookings confirmed within 1 month from the creation date (valid for travel until March 2013).
Name change fees are not covered by MFlex and will incur the standard £100/€125 per name change. M-FLEX is valid on scheduled flights only.
So - no admin fees but £100 to change a name and you still have to pay the higher price if it's gone up.