Human Modifications

Self-enhancements include robotic limbs, altered genetics, and mods. All of which are expensive. They are widely available to civilians, but there tends to be a social stigma associated with obtaining them without being part of the military, or in the line of work where they're commonly found. Even if someone were to lose a limb in an accident, the most common procedure would be to clone a new one. Robotic limbs come in all shapes and sizes, with some mimicking the muscle structure of the lost limb, and others being less conventional.

Although cloning a limb is often the best choice in most scenarios, it often depends on the location and economic status of the individual. Cheap plasteel or other lightweight and decently durable materials are often used in the creation of rudimentary prosthetics, which get the job done but typically lack sensory functions and other advanced features.

More advanced full cybernetic/robotic integration prosthetics are more expensive, but keep a full suite of features, including capabilities unique to a mechanical appendage. These sorts of prosthetics are more common in the military and private paramilitary organizations, as well as within shadier circles. While more advanced than a rudimentary prosthetic, the mechanical integration comes with a slew of issues and the potential for a lifetime of sensory problems.

Finally, the most expensive (but safest) would be to recreate the lost appendage through cell culture manipulation. While the process of creating the arm is not too cost inefficient, it is fairly pricey, and the operation becomes far less tenable after the consideration of the surgery cost- which is arguably the most difficult part of the operation.

Altered Genetics
Though altered genetics exist, the scale is generally within the realm of cosmetics. The realm of increases in strength, speed, and intelligence are possibly on a technical level- but practically are never seen. There are thousands of possible genes, all interacting with each other that could potentially alter any of those traits- in some cases making manipulation extremely difficult, and in other cases only manipulating the outcome in part.

Without getting into the realm of long, sweeping genetic changes to the genome, it would be impossible to alter individuals on a grand scale. Ethical and moral issues raised with this topic have put such concepts on the backburner, though there is vested medical and military interest in continuing the topic further.