Separately would be cheaper. To my knowledge, except with shitty companies (UPS, Fedex, DHL) you shouldn't have to pay for packages under 100$.
If it's with EbayBanned, they will ship separately, that you want it or not. Yeah, for one single relatively small (6 items) order I got 4 packages.
But, I didn't pay more, it's just that they didn't arrive at the same time so I had the fun of going to the office like 3 times during the week, and I'm waiting for two that should arrive monday or tuesday... It's just a pain when you don't have a car and it's 3$ per bus ride.