Better whips will mean more durability, which is nice -- having your toy break in the middle of play makes a sad panda. It also means different sensations; I won't say better, but every type of toy has a unique sensation. If you like what you got, I'd say buy a few spares and do the happy dance. There's no reason at all you have to use expensive stuff.

As already mentioned, if you're willing to shop around or consider assembling something on your own, there are a lot of ways to make cheap gear.