I am actually going through the exact same thing, but I did buy some BDSM gear for partner play last week. I'm currently conversing with a possible companion at the moment, so I thought I'd just get a few things for the hell of it.

Eventually you won't be single, so if your heart is set on buying stuff early, then totally go for it

It depends a lot of BDSM gear is very hard to clean, so it greatly depends on what your buying and how you intend to use it. I have toys for my sub and my sub alone, and toys I can use on others. So my toys for my sub are very specific to her. Meaning I've bought them to match her attitude I suppose. Paddles and such items not made of leather are always easy to treat. Floggers and the like not so much.

Like geekkink said, i'd get things that were sanitizable or things that won't come into contact with any body fluids. Anything that will break skin or come into contact with blood or other bodily fluids which can't be sanitized should be single partner toys only (ie: rattan canes, floggers or whips, etc. that will draw blood, porous toys or tools used on the genitals, obviously needles, knives that cut skin, scalpels, branding tools, etc.). Anything like this you should plan on giving to any partner who they come into contact with the fluids of. my Mistress is in possession of a cane that was used on me during a demonstration at a party and drew my blood so it was given to my Mistress. Cuffs are usually safe to use on multiple people unless they cause the skin beneath to bleed. Gags can be reused if they are washable. Impact toys like floggers and paddles that don't draw blood can be used on more than one person. Now, if you are a bottom, there's nothing wrong with purchasing toys which any number of tops may use on you. Even if they break your skin, they can be used on YOU (and only you) again as much as you want unless they break or a porous item eventually rots from moisture or something, except in the case of things deliberately intending to break the skin like needles and scalpels which should only be used on anyone if totally sterile. If you are a top, personally i wouldn't purchase anything expensive unless it is safe to use on multiple partners until you have someone you expect to be with for a while so that you can reuse the item. If you do purchase some toys, you might consider going to some parties or other events to have a chance to play with them .

I agree with the others. If there is something you know you will want and it can be cleaned go ahead, but you may find that partners have different taste and preferences so if you end up in a long term relationship it might be something you want to buy together! =+)

Are there things that you know you will enjoy, that don't depend on having a partner?

For instance: I bought my first strap-on dildo to use on myself, because I thought it was really pretty. I was pretty sure that I wanted/needed it for myself, whether or not I had a partner who wanted to receive strap-on play. Once I had it, though, it was much easier for my partner to express interest in it.

If you like/want/need to get hit to enjoy sexytimes, it can be much easier to say "here, hit me with this" if you already own a toy. I feel like owning my own toys gives me a stronger sense of myself, rather than having my sexuality be dependent on a partner (I've never been monogamous, though, so I am probably coming from a different place than many people here). Also it means I don't have to wait until a certain point in a relationship to try something I know I like (I usually wait a long time before bottoming to someone, but I will top someone I am just seeing casually), and I don't have to get rid of (as much) stuff when a relationship is over. Because it's my gear.

I'm in the same situation. I've got a list of things that I want, and I'm starting my collecting with things that I can use solo, then go on to the ones that I'll mostly likely use with a partner, and so on and so forth. (And I wouldn't worry about a collection scaring anyone off- It'll separate the kinksters/adventurers from the vanillas. Pre-screening made easy. ;])