This year the cost of taking the test is at least £65. If you take the test after August 2013, it will cost more: £80. The cost for those outside the EU for any time in season: £100. The reason for such a hike in prices is due to a higher demand for places near the end of the test period (i.e. October is more expensive than July).
Cost of the UKCAT can be reduced (even waived) with the receipt of a bursary. The earlier you apply for your Bursary the better, as applications can clog up. This delay would play into when you are able to take the test. Forgo any strife this can cause and apply for the UKCAT bursary as soon as possible. Pearson Vue will start accepting bursary applications from 1st May 2013. They will do so until 5pm 20th September 2013.