I think the idea is to contact the advertiser by PM requesting that type of information vlad - as many posters will know the person advertising the place people are often reluctant to put details for all & sundry to see.
As to what is a place worth in Udon, I guess it is more a case of what people are willing to pay & that could also be a reason for not saying specifics up front....
If you want some sort of guide then I will try but others may disagree with me...
How much a month depends on location & property plus, if furnished, quality & quantity of furnishings.
You can pay between 3,000 & 12,000 a month depending on the above....personally I have found (after a fair bit of searching) that I can find a very acceptable property in the 5,000 to 6,000 bracket - but if you want high quality expect high prices!!
Deposit sort of depends on what you can damage & what bills you can leave behind - expect most landlords to want 1 to 2 times monthly rental...
Length of lease.....depends how desperate the landlord is....

I would expect that for (for example) a month lease the landlord would want a fair premium over the monthly rental for a years lease. A years lease paid up front should give you a reasonable discount on a monthly rental. It is a fine balancing act for both landlord & lessee. The place could be well worth the money, but the neighbours could be from hell - the place could be perfect but the landlord decides to sell after a month.... You really 'pays your money & takes your chances'......
When looking at rental it is really well worth looking at AEK apartments first & this will give you a very good guide/standard as to what you should pay for something else...on the grounds that if nothing compares then it is probably a good idea to settle there for a month or two...