[WTB] Second-Hand past gen asic miners

Good morning/evening/night everyone!
I would like to take advantage of this as my first posting on this forum to thank everyone for all the information shared here, because I have learned a lot these last days by following the most up-to-date issues, thanks to everyone.

Shortening the story, I invested in China's mining Genesis last year, and this year I got enough funds to invest in some asic-type bitcoin mining machines.
So here I would like to say that I am looking to buy second-hand past generation machines. I'm from Brazil and I have a budget of

$ 1000 - $ 1300

I accept proposals mainly from past generation machines with PSU, such as:
s20,
s5, s5 +, s7, s7 +, R4
avalon 6, Avalon 721
M1, etc.

I accept offers from other models not mentioned.
I have how to pay in bitcoin, paypal, bank transfer, etc, but would like to do business using escrow.

I searched the internet and saw that today it is possible to acquire by aliexpress for example a bitmain S5 with a non original PSU for about 300 dollars, I found it expensive because some time ago was around 200 $ and this machine would only make some profit if the people had a favorable or free energy situation.

I would like to invest about Us $ 100 for every 1Th / s so as to gather all the bitcoin produced and make 4 scheduled purchases with the same buyer over 3 months with individual payments.
I am interested in receiving the goods by private carrier with insurance and tracking, for example. DHL, FeDeX, UPS etc.

The idea is to get the highest number of TH / s that my money can pay and buy more machines in 3 months with total production with the same vendor if possible, to make it easier for me to manage my life.

Thanks again for everything to everyone.
And sorry if I broke some rule of the forum or if I committed any offense.
Please apologize for any grammatical errors, I have been trying my hardest with a language from outside my country.