I'm prescribed a daily testosterone gel from my doc for low t. It works well. The dosages are lower than bodybuilding doses.
A typical test replacement dose is around 100-150 mg of testosterone injected weekly. A bodybuilding dose starts at 500mg weekly and can go into the grams of test per week. Your testicles shrink, but they don't shut down completely. Once you stop you can bounce back, but typically the expectation is that you will be on it for a long time. The long term benefit outweighs the risks.
I don't know about taking a steroid RC. There isn't a lot of research behind most research chems, and I think that researching something you would be taking long term to replace your hormonal system is essential. The plus side is that steroids have never been cheaper or easier to get then they are right now. Illegal chinese powders are pharm grade, and they are everywhere.
If you don't want to go to a doctor, then your next best bet would be to head over to
https://www.reddit.com/r/Steroidsourcetalk/ and research which of the vendors there would be your best bet. I can't reccomend any because I have a prescription.
There are places that will do testing to determine your blood levels before and after starting. If you are going to go the illicit steroid way and want to do it as legit as possible I would look into this.
Generally for TRT you would inject 100-150mg of either testosterone enanthate or testosterone cypionate. Pretty much the same thing for this purpose. These are slow to release into your body because of the esther (the enanthate or cypionate) that your body must remove before using the testosterone. You can also get testosterone. This is watery as opposed to an oil. It is immediate, and would translate to being something like the daily gels you put on. Since there is no esther attached your body can immediately use it, but it breaks down quickly. For this reason it is a daily use steroid. I wouldn't reccomend anything other then those three for a test replacement therapy.
Obviously the best way is to go see a doctor. There are private doctors in the us that will prescribe testosterone for anyone with a low test test (hah!) Often they fall under the medspa label, and will cost you your second born child, but at least not your first born. Here is an example:
http://www.physicianartistry.com/lowtestosterone.html If you do this then ignore the bioidentical hormone pellet nonsense. It doesn't work, and it is just gimmicky overpriced crap using the same chinese test powders as a base. Gels or injections are your choices. There is a patch, but apparently there are absorption issues with it.
Hope that helps. If you have more questions then don't hesitate to ask. I'm happy to answer what I know, and to try to find out what I don't.