I don't think it's ever safe to buy an SSD these days. It seems like if you wait a week, you'll be able to pick up something cheaper and bigger, such is the march of technology (and discounts). That doesn't mean you shouldn't jump on a deal if you need an SSD, like this 500GB Samsung 860 EVO for a mere $120.
Normally $150, if you hit up this eBay deal, you can take 20 per cent off the price with the PHOME20 coupon code.
The 500GB is the spiciest deal, but you can also drop down to 250GB ($86.40, from $108) or bump up to 1TB ($228 / $285), 2TB ($620 / $775) or 4TB ($1685 / $1348).
[eBay, via OzBargain]