Ebay as a buisness/tax implications

amazamum

Hi there,I have had an ebay account for about 3 years now,It first started as just selling the kids old things but in the last 6-10 months I have started selling other bits and pieces that have been bought from shops.
My question is I am thinking of setting up a new account with ebay in which I will buy from a shop/manufacturer to hopefully sell on at a profit and declare everything to the tax man(boo),the only thing is will they be able to check up on my previous ebay account and see what I have sold and I could end up paying a large tax bill(nothing huge but anything would be large to my finances) from previous sales.
The new account would be registered to my home address as with the first one and would go into the same paypal,although if anybody knows how to get a new one just for this new account please let me know.
How do I go about registering the new account with the tax man and what documentation would I have to keep regarding things bought and any sales I hope to make.
My husband and I both work part time so how would this effect how much tax we pay(we also get wtc for 2 children).

Thank you for anyone who can help me :T
sorry about all the question but I want to be sure this is the right way to do anything before I go ahead.

windswept

gah! my first post to you hasn't shown up , the rules say that you should register within 3 months of starting to trade or risk a £100 fine.
you don't need to register your ebay acount, just the fact that you are self-employed.
if you have used up all your tax free earnings in your day job, you will be taxed at 22% on any profits.
the issue about wtc. I can't help you with , perhaps you should ask on the benefit board, or ring hmrc.
at the very least, have a look at their website, it explains everything in great detail.
you should keep receipts for EVERYTHING, postal, items bought to sell, tape, paper , ink, in fact anthing soley used for your business is an expense. you also need to know about "cost of sales", but I have to go shopping now, so pm me if you want to know more.