As a small business owner, can I deduct my fuel costs and other required items that I need?

I'm a small business owner and use the small business regulation (may calculate on my sales no sales tax or input tax claim).

Since I buy many used things from private (tires and rims) I often drive over 150km (private car). Can I enter the driven km at the EÜR as expenses? And how does it look if I buy a laptop for 200 euro, I can also specify as expenses for the EÜR? And if so, where should I enter it?

Example:
I buy from someone private the 150km away lives his rims for 500 euro. Then buy me a laptop for 200 euro.
Sell the rims on private for 1000 euro.

Then I have to enter the following at EÜR or?

Output:
500 euro for rims, 150km x 0,30 euro = 45 euro,
Laptop 200 euro
Total: 745 euro

Revenue:
1000 euro sale of the rims
Total: 1000 euro

I would then tax the 255 euro or am I wrong?

Yes, can you fix everything.

Business trips with priv. Cars you can then sell with 2x 150km x 0.30 euro, because the drive home back to your establishment is one of them. But it seems to me you should consult a tax consultant. You can also spend these expenses as business expenses

Are you sure that I can fully calculate the round trip with 0,30 euro? Since I read that you can only calculate the way there as in the normal tax return as a private person

I myself have such a store for a long time and make my income tax return without complaint of the FA itself. But as I said, you seem to have too little knowledge of it. And a tax consultant is already paying more than that

And you are a (single) entrepreneur and not a private person in terms of EUR

Do you also sell wheels? How do you do that if the private person does not give you a receipt as proof how much you bought the goods? And how do I prove how much I have sold the wheels?

Without a receipt / bill do not buy anything for your business. You absolutely need them as evidence in the FA, if an audit takes place. This can always take place within 10 years.

The problem is that 99% of my purchases are private and 99% are private. Since it will be difficult to get a receipt with name and address and signature… How should I proceed there?

You may not allow this as an entrepreneur without a receipt / invoice to buy or sell. How should you proceed?

No, it's not that easy:-)

Because the miraculous German tax laws hold many surprises ready.

Is it enough if I take a picture of the ad from eBay ad and just enter the surname and the address on a receipt block as proof? I have address, because I pick up the from there but no signature…