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 following 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]