What is the best solution for organizing a data archive + their backup?

Question

Hard disks

There is a problem, and I'm looking for the best technical solution for it.
Task:
At the moment there are about 2-3 TB of data, data growth is about 70-100 GB/month.
A solution needs to be found to store these volumes. Data will be accessed approximately 1-3 times a month (not all, of course), for the vast majority of data, you just need storage. You may not be very mobile, but you need to be very reliable.
Remote access to data is not needed, but be sure to backup all this data. I will most likely do backups manually, so I’m not considering RAID and software backup options yet (although, if there are weighty arguments, I’m ready to reconsider my position).
Well, an important financial point: it is desirable that the decision comes out no more than 15-20,000 rubles. Although, again, if it is rational to spend more, while receiving a large increase in utility, I am ready to change my attitude towards expenses ^^.
The data will be pumped using a stationary computer. It has USB 2.0/3.0, eSATA, and some sort of Ethernet outputs.
Thanks in advance for your answers!
PS If we talk about HDD, then the choice is between the three companies WD, Hitachi, Seagate (selection priority in descending order).