I don't want to suggest it but if your going to do it then better know this.
Once you start HRT you have to take Estrogen for LIFE- you can lower doses once you opt for SRS or get castration.
I recommend bio hormones as the risks for it are very low. It really depends what you mean by this post though. do you want to get changes which are noticable? or do you want something small?
Self-medicating has disadvantages in that you can't monitor you hormonal levels so you have no idea if the regimen your self-prescribing is doing any good.
Now, you need Anti-androgens too.
I suggest you lose wieght in a healthy way if your obese as you don't want heart disease, stop smoking, drinking, any drugs, and start eating healthy.
Make sure your liver, kidney, lungs,, heart, blood pressure, cholestrol and overall health is in good condition.
Do NOT take premarin or any synthetic hormones- it is much more dangerous and likely to get you caught.
I suggest you do some serious research on how to carefully adminster the drugs you plan on self-prescribing, what effects it has on other drugs & foods and to be sure you have no serious medical condition.
Seriously though if your just planning to take it for 1-3 months and stop that's just stupid because in that time frame in you can see a therapist and if they feel you your ready you can start HRT safely, cheaply and effectively.
If your planning to take it for 1-3 yrs- this is very serious as you may over-dose, have serious complications if your not aware of medical conditions or if the medicines don't suit you. Also if your an adult around 30 and especially 40+ you can likely incounter a problem
My suggestion- See a therapist if you can and have money too- you may find out your not really trans, you may start HRT sooner than you think, and it can help you.