I cannot post in the Dolz section for some reason, so I am putting my question here.

I have got the free Lana Lane card. I have 0.0 POL and 0.0 DOLZ. It says I need at least 0.1 POL to be able to sell card. Do I really need to buy POL somewhere to be able to sell NFT cards? Or is it enough to buy some DOLZ for that? I see that the minimum price to buy DOLZ is 25 $/€. I do not have any idea how POL can be bought and didn't find that information in the Dolz section when searching for it.

Yes, you need the network's native token to trade cards.

To sell your Lana Lane you need some Matic.

If you as nicely maybe someone will be able to send a bit your way :)

I have got the free Lana Lane card. I have 0.0 POL and 0.0 DOLZ. It says I need at least 0.1 POL to be able to sell card. Do I really need to buy POL somewhere to be able to sell NFT cards? Or is it enough to buy some DOLZ for that? I see that the minimum price to buy DOLZ is 25 $/€. I do not have any idea how POL can be bought and didn't find that information in the Dolz section when searching for it.

If you sell you Lana Lane card you get Dolz for it .
You can't sell your Dolz for money.
In a wallet (like Metamask) you can swap your Dolz to Matic (this cost some Matic)
Then you can sell your Matic for Money (to credit card or bank account) but this cost some money
So to sell only 1 card I think it costs more then you get for it.
Also you cant sell your card directly, you put it on sale so someone can buy it. But many have the free card:
see dolz.io - market - more collections-Lana Lane: there are 5100 cards and 20 on sale.

I do not want to sell cards for money, but to be able to buy another card. So far I cannot sell or buy anything and it seems like that will not change even if I will buy DOLZ. So my question is: what do I need to do to be able to pay for the gas?

@Alkasyn made the suggestion...

If you have a friend you can ask them to send you a few POL(Matic ) gas tokens
Then you can Purchase some DOLZ with a credit card.
After you Purchase DOLZ, you can Swap a few DOLZ for More POL ( Matic )
Then you can Send back to your friend the POL that they Loaned you.

Now you will have Both POL and DOLZ in your Wallet.

Note: Any Friend can Send to your Wallet and you Do NOT need to have POL to Receive it.
For a Friend to Send to you. You need to Share your Wallet Address with them.

Another Option is to try and Use UniSwap, I think you can buy less of a Minimum

Buy POL at UniSwap
https://app.uniswap.org/explore/tokens/polygon/0x0000000000000000000000000000000000001010

I can buy some DOLZ with credit card, that's not a problem. So, after buying them, will I be able to sell and buy cards or do I still need to trade some DOLZ for POL? Or is it done automatically when you are buying/selling cards?

I would like to avoid any unnecessary wallet transactions as I am new to the crypto and it's really ***** to start with it.

do I still need to trade some DOLZ for POL?

If you are using a 3rd party Web3 Wallet Manager and not the 1-click wallet.
Then YES, you still need some POL.

But you can not swap DOLZ to POL until you already have some POL for the Transaction fee.
You need very Little for that 1st Swap.

A friend can send you like $0.10 ten cents worth so you can make the 1st transactions.
Then you Swap some of your DOLZ for POL you probably only need to swap 20 DOLZ to POL to get started.

and then Send back to your Friend, the POL they loaned to you.

Always Copy and Paste the Wallet Address so you don't make a typo mistake.