I have just checked coupons. The lowest price I could get is 149.99 USD for ThundeaL PG500 (in Banggood). You can create price alert here, copy coupons and view price history. Let’s see what best price is ATM.
Latest coupon and price update (UTC):
Banggood (149.99 USD)
Banggood warehouse is located in China. Is it a reasonable price for this item? IMHO this is a good price, coz it’s lower than average (159.21 USD) I found coupon for you. Check this out.
Link: Banggood product page
Price without coupon: 159.99 USD
Coupon (149.99 USD): BGce5aeb
(CouponsFromChina.com tip: apply code in your basket (cart) after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BG589b2e, BGsaleSaS, BGSaleFeb8, BGSaleAD, BGa5e78e, BGMARCHSALE, BGProjcc, BG194a55, BG66949d
(I don’t think these’re gonna work, but you can try ’em out anyway)
Aliexpress
Click here… to search for ThundeaL PG500 1080P Android Projector on Aliexpress
Here are coupons that you can use.
Price history and price alert
Here is price history (for all/most countries) for ThundeaL PG500 1080P Android Projector.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).