You’re not going to be able to get full-on MPC emulation for less than $5, but Akai has included a ton of great samples and features stripped straight from its legendary MPC series:
Turn your iPad into an MPC. With more than 1,200 samples, 50 editable programs, 80 editable sequences, and iconic MPC workflow, iMPC is the first app to bring the look and feel of the classic Akai Pro MPC to your iPad. iMPC includes everything you need to create a beat quickly and easily, including built-in effects, plus the ability to create new sequences and record and overdub beats. Time correction from 1/8 note to 1/32T with variable swing, and Note Repeat from 1/8 note to 1/32T with latch control are also built in. The app’s built-in sampler can record samples three different ways: using the mic on the iPad, using the line input on the iPad, or using the multi-touch turntable interface in iMPC to record samples directly from iTunes or other music libraries.