Sublab by Future Audio Workshop -

If you create trap and hip this is a perfect plugin for you. If you like sound design then it's also for you.
You can create powerful and punchy 808's in seconds or just load up a sample or preset. SubLab comes with hundreds of samples, 6 bass packs and we can drag and drop our own samples into the sampler.  You have the ability to layer, widen, sample or distort any kick into an 808 or sub bass. Create our own unique sounds. The new psychoacoustic sub-bass oscillator makes for some new capabilities. The cost, $40. 

Orb Synth by Hexachords -

Normally $59 dollars now you can get for $5 bucks.  Orb Synth is a wavetable synthesizer that has two wavetable oscillators, each with its own filter. Two ADSRs (envelope generators) and many more ways to tweak and modulate its sound. There are dozens of handmade presets you can use or create your own special sounds with the modulation matrix.


Sektor by Inital Audio -
This was built for trap and hip hop. The sound is amazing and the price is as well, $29. Sektor is a polyphonic synth with 2 wavetable oscillators and a sub oscillator. Sektor also comes with 750 presets. Another great advantage of having his plugin is the ability  to use the the two effect racks.  They include a reverb, delay, distortion, chorus, phaser, compressor, stereo shaper, trance gate and a 4 band eq. 

SLAMMER by Klevgränd -
This is a drum slash percussion instrument plugin that is really fun. Slammer is a multi-sampled drum plug-in that contains 30 different instruments and the ability yo edit each one. Being able to customize each setting like the pitch, the filtering, the effect sends, decay time and the velocity. If you want natural acoustic or heavily distorted and compressed drum sounds this is a great plugin for $29.

ElectroNylon by Sampleson -
This unique instrument combines the flavours of both  nylon guitar and electric piano. This hybrid truly is one of a kind. One great thing about this plugin is how it allows you to go from a Nylon Guitar to an Electric Piano just by moving a slider. This sounds awesome in any style of music and you have the ability to play with some effects such as chorus, drive, reverb and an ambient fx.
For around $40 this can be yours.