Of course, the more the merrier! One of the key aims of this site is to get all the UK race photos in one place, to save us all from having to look on 17 different websites every week. You may think your photos aren't the best, but that doesn't mean no-one will be interested in them.
Once signed up you can create your own prices, so you can value your photos as high or as low as you want. Some photographers charge upwards of £15 for a JPEG download, others as low as £3. There's space in the market for professionals and amateurs alike.
That being said, no-one wants piles of poor photos of themselves. If the majority of your shots are sharp, in focus, well-framed and well-lit, then there's a home for them on R&R.