Mabey for Rafel best is, take this job, and continue to look for other options ?
Actually, that's a pretty bad strategy. The danger of getting stuck in a job that doesn't pay enough to cover anything more than a very frugal existence is too high. Best to find a good-paying job BEFORE he comes. Like I said, life in Warsaw is expensive, and anything less than 5000 PLN netto is not enough to justify moving to Poland, rather than trying your luck back in the Netherlands or in another western country. The critical factor is how many EUROS you can put away at the end of the month, which should be AT LEAST 500 Euros (2000 PLN). Even at 5000 PLN a month, it's going to be difficult to put away 500 Euros per month, unless you live really frugally in a shared apartment.
For orientations sake, your monthly fixed costs (housing, utilities, internet and bus/tram ticket) will range from 1000 to 1300 for a room in a shared apartment, from 1500 to 1800 for a studio apartment, and from 2000 to 2500 for a basic one room apartment.
For a single male, food can be done for 600 PLN a month if you cook practically always at home from scratch and eat a mostly vegetarian diet based almost entirely on potatoes, cabbage, onions, carrots, apples, dried beans, macaroni, rice, flour, bread, yoghurt and eggs. During the summer, your range of vegetables will be a bit larger, but during the winter, things like tomatoes and peppers will be a luxury. An occasional chicken breast or can of tuna fish will be a special treat, as will a cup of coffee in a cafe or a bottle of iced tea, for example. You eat a bit healthier because you're going to cut way back on sugar and butter, and other high-priced processed items. The types of sausage that you can afford at this level are all pretty much inedible. You're going to be spending a lot of time shopping in various stores, markets, vegetable stands and bakeries to get the best deals.
Otherwise, it's going to cost you quite a bit more, expecially if you eat out. Unless you're frugal, it can easily exceed 1000 PLN a month.
Drinking and smoking (tobacco or otherwise) are significant expenses that will drastically cut back on your ability to save, and may even sink your budget deep into the red. Same with entertainment expenses.
Don't forget about set-up costs, which can range anywhere from 1000 PLN minimum to several times that for one-time items like furniture, bedding, cookware, paper supplies, computer equipment, bicycle (a cheap one, with a serious heavy-duty lock; bicycle theft is the number one sport in Poland, and any bike that isn't cheap will quickly be stolen), and, of course, the deposit on your room or apartment. Nor about reoccurring expenses such as clothing, household items and replacement bicycles for the ones that get stolen,
Nor about the cost of (hopefully) occasional trips to the doctor or dentist. Don't let preventative care slip even if the money is tight; you can't afford an extended illness or expensive medicines or treatments. For God's sake, make sure you get your flu shot; six weeks at home in bed can ruin your budget for many months.
Also, even if money is short, get some sort of physical recreation: swimming, squash, whatever, even jogging. And some cheap or free cultural stimulation as well; standby tickets for the theater and opera are quite inexpensive, and if you make friends in the arts community, they can even weasel you in for free. It's probably the cheapest way to add variety and spice to an anotherwise frugal and monotonous existence.
A big money saver is knowing the local language well and networking with graduate students, who know the secrets of living cheap in the city, like where the Hare Krishnas will be passing out free food. All of your spare time should be spent beefing up your Polish. Sadly, it still happens that unscrupulous merchants take advantage of clueless foreigners (rare, but it happens). Getting "adopted" by a Polish family helps a lot, too, and very few people over forty speak English.
You might scrape by on less than 5000 PLN a month for a year or so, maybe even two, but you'll be burned out at the end, and have little if anything saved up. All in all, it will probably not have been worth your time to come to Poland in the first place.
