It depends, as there is lots of variation from figure to figure. Nowadays, Hot Toys seems to anticipate, and exceed demand pretty well. In times past this wasn't always the case. And in that sense, you might be able to find figures cheaper on the secondary market, or with SSC coupons if you wait. BUT. . .you never know. Sometimes figures can sneak by you, sell out quickly, and be hard to pick up for a decent price later if you don't pre-order with SSC early.
But I agree with the guidance that you not pre-order from eBay. You may want to pre-order from other, legitimate sites based in Europe though. I don't know what they might be, but it could be cheaper even with their markups than dealing with custom fees and shipping from importing directly from SSC.
I live in the U.S., and sometimes order from PopCultcha.com, which is based in Australia. They are an official HT distributor, but the shipping is pretty dang cheap for overseas shipping, they have great discounts from time to time, and they'll frequently have items that have sold out from U.S. retailers.