13.3 inches, with 1080p resolution, and Matte non-touch display.
That's the killer combo there.

Core i5, 8GB DDR3 RAM, 256GB SSD**.
That's also the killer combo.

Brand new laptops with those specs retail close to the $1,000 mark.

(**However some people, not all or many, NEED more storage. You can use cheap and reliable external hard-drives. Or you can use a hybrid HDD-SSD drive. It's a personal decision.)

1) Try googling for a specific model:
http://bfy.tw/wza
2) Then look for reviews of that specific model
(use well known reviewers)
3) Look for prices, eBay might be your best bet:
http://www.ebay.pl/

As some people have pointed out already, getting a used or refurbished Lenovo ThinkPad (a 2013 model ?) is probably the best deal. New ones are very expensive, but the old ones work as good as the new ones. And Lenovo has a reputation for having the best Keyboard and Touchpad out there.

There is the Dell XPS 13 Variant (non-touch 1080p 8GB 256GB) which ticks all the boxes, but not sure about its availability for you in Poland. I hate Dells, and this is the one exception they nailed.

There is also the ASUS Zenbook UX305FA which is pretty good and cheap, the only downside is the non-backlight keyboard, and Core M processor which is slower than the Core i5 processor. It's about as fast as the old-ULV Core 2 Duo processors from 2011, so take that as you may.

Good Luck ; )