Presently is 400$ per gtx1660 Ti a good buy? Now that no one knows how long mining profitability will keep up, is this a good price to buy or I should let go and wait for later? The offer consist of just three of this graphic cards right now, what do you say?
The price is definitely cheaper than in my country (about $500 right now for 1660 Ti). With 1660 ti you can get about 30 Mh/s for each card which can earn you $4/day right now and with that you can hit BEP at about 3-4 months and if you need to buy other part for the mining rig then you'll need more time to break even. Keep in mind that the income right now is very high (it used to be sub $1/day last year and about $2/day early this year) and can decrease as the network difficulty keep increasing, the activity of ethereum network, the talk about EIP 1559, etc. At the end of the day it's your decision whether you are comfortable or not with this kind of risk. You can probably sell the card for $100 if the market crash later and a lot of card flooded the market.
There is no point in selling the card for 100$ when ethereum mining is not profitable anymore, I would advice to keep mining because crypto space is season base, gather the coins in bear market and wait for bull season again, there are many who are now rich because they keep mining Ethereum in 2018 after bears took over the market, now they are in millions, satoshis will be satoshis but value worth us all that matters