$47.99 – JUNTEK MPT-7210A Solar Battery Charger MPPT Controller Digital Control Boost Voltage Module High Conversion Efficiency Durable ABS Material 12-60V Input 15-90V Output Power Saving Eco-Friendly.
I have just checked coupons. The lowest price I could get is $47.99 for JUNTEK MPT-7210A Solar MPPT Controller (in Banggood). Price history, coupons and price alert are available on this page. Let’s see what best price is ATM.
Latest coupon and price update (UTC):
Banggood ($47.99)
Banggood warehouse is located in China. Hmmm… There is no active coupon in Banggood at this moment. Is it expensive? Hmmm, price is higher than average (which is $47.19 right now), so better set price alert down below…
Link: Banggood product page
Price: $47.99
Additional Banggood coupons: first page and second page
Aliexpress
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You can use link bot to get even lower price:
Click here to search by yourself. Here are coupons that you can use.
Price history and price alert
Price history (for all/most countries) for JUNTEK MPT-7210A Solar MPPT Controller is here. The lowest price was: $45.99.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).