Prices might get cheaper if we get a US free trade deal and can import goods cheaper from there, I can't wait until I can order from the US via Ebay without getting robbed on tariffs. What exactly does the EU do in terms of big tech anyway? about the closest they get is leeching off US big tech firms financially through fines.
Erm you're aware there is a difference between tariffs and VAT aren't you?
Tariff's are applied before any specific local sales taxes, usually to protect the local industry - so where there isn't one tariffs may not apply, or may only apply for certain times of the year (for example your growing season).
VAT which is the main reason you get charges on importing stuff from outside the EU is a different matter and is applied to almost everything usually at a very limited range of rates.
Given the UK government used to charge 17.5% as the standard VAT rate, then dropped it to 15%, then back up to 20% all without any issues from the EU what makes you think that your computer parts will suddenly get that much cheaper if we get a free trade agreement with the US, given that we'll still be paying vat on imports over £15 (down from the £18 it used to be, again nothing to do with the EU).
At the moment for personal imports IIRC duty is only charged when the goods reach a certain usually high threshold, whilst VAT is charged from the moment the goods come to £15.01.
The only way you get away from VAT is if the government raises the vat threshold for personal imports (not likely, especially in regards to it making a difference for computer gear), or we enter a customs union with the US, in which we'd be very much the junior partner with no say (unlike in the EU where we are an equal partner at the minimum, and have a veto over a number of important matters).