The site does accept PayPal payments so you'll be able to dispute your transaction if they happen to be illegitimate if you do choose to buy this.
Do they refund people by locking funds from the sale or will they refund you regardless of PayPal being able to get the funds back from the seller? I'm sure there is a way to work around that, because it will take some time to have the products shipped, which grants the shop to cash out the funds before the buyer opens a claim.
There are some reviews from people having bought stuff from minermaster on
youtube, so it seems that there is some legit activity going on. I like that they have their own branding on the product, which adds to their legitimacy. The only point of attention is that they use whois privacy, but since it is the main company itself, it may not be of much importance in this case.
I've used PayPal in the past, and you've got 180 days to file a dispute or chargeback a transaction through their platform. I have personally not experienced a chargeback as a seller in a while, and in the past when I had chargebacks from selling on eBay, I had funds in my account and they were simply removed when a chargeback was filed against me. I'm pretty sure that PayPal removes the total transferred original amount from the account the money was sent to, and the balance on that account turns negative and they absorb the rest of the costs. PayPal also sells debt to debt collectors in the event that someone can't pay off the negative balance in their account in the US too IIRC. Nevertheless, you'll be able to dispute and get your money back if you legitimately haven't received the product you purchased within 180 days, and PayPal's extremely buyer friendly in the first place.