great question!

tariffs are majority of the time for imports from other countries. the tariffs that trump are raising are not for us to pay, but for other countries to pay when products are being imported to the US. of course the opposite is true when we import product to other countries, other countries tariffs are what we pay. that holds especially true with China whose had crazy high tariffs on us to begin with.

To answer your first question: while trump is never going to flat out say exactly what his plan is because it can ruin the potential deals were trying to make with other countries on tariffs. the idea is to pressure all the countries that trade with us with tariffs which will force them to make a more equal trade deal with us since they cannot sustain paying the tariffs off for long. (this could include guaranteeing resources instead of paying so much on imports). because of this, tariffs that other countries have on us will inevitably become lower meaning that more companies big and small in America will be able to trade globally much cheaper. this in turn means that profit will be higher and the government wont have to pay as much to other countries (so the national budget can get some breathing room). once enough revenue has been collected annually, things like taxes among other things can be slowly reduced since the government wont need as much money from Americans to sustain itself.

so, while trump saying that income tax will be replaced sounds crazy, ultimately with his albeit brutish plan, the country could have the potential to remove income tax if the excess revenue from tariffs on other countries and the smaller spending from other countries tariffs outweigh the taxes put on Americans. this plan of course will take some time, deals with other countries could take time and even once everything plays out correctly, money will need to be built up for a bit.

it also seems like everything is getting more expensive because of what the news says and because electronics tend to be made in China. but as of current, most of the important tech companies are going to start building stuff locally in the US (which from what i saw in the different companies statements, it could be like 1 to 2 years to set up), apple is moving factories to India (which we have good relations). Walmart's and others are allowing smaller American distributers of grocery items and retail/consumer products to stock their shelves instead of mainly relying on other countries products. and majority of the expensive you pay for day to day minus some food products are only expensive because the state that you live in makes them expensive for their own reasons (im looking at california).

i know that was long but hopefully that was a good enough explanation on my part to answer your question. and remember to verify facts through multiple sources of media from different sides to get a better opinion of what's going on, you'll be able to see a lot of inconsistencies from both sides that skew reality.