Should I buy another flat screen now while they are still relatively cheap?

I think that costs on anything electronic will go up, particularly those components in the US made with parts overseas (and that is almost everything). Some companies will be legitimate in passing the cost of the “t” word to the buyer, others will be price gouging to increase profits. Be wary of the claim “our product is made here in the USA”. The fact is that the USA does not manufacture many electronic parts here anymore, and have not in many decades.

My 60 inch Pioneer Kuro that I still have and use daily was purchased in 2007... and  still functions and looks great!

OP I bought my LG 65 OLed 4 months after release 50% off. Texasblue1959 I bought 100. 

Following through with this mentality you should maybe think about other items that would also be affected. Why just the TV ? Don't stop there. Get a new refridgerator, dishwasher, washer/drier, AC units, new car.  Furniture is way more expensive than the TV and as you are suggesting, most items will be subject to increases. So why wait? Go for it.