A little confused by your question here.
Whether the DSO is worth $250 or not is easily checked by looking at what is available in your area. It sells at a premium as there is little, if any, choice in the UAE. You have stated as much.
Are ATTEN DSO's any good ? IMHO, Yes. I own a couple and the build qiulaity is good. You have to take a close look at specifications though as some are marked up as 60MHz or 100MHz bandwidth, yet only have adequate sampling rates for much lower frequency 'one shot' non repetative signals. Divide the sampling rate by 10 as a good guide to true real time capability.
IIRC $250 is not much money in the UAE so to answer your question....yes $250 is a fair price in your scenario. I paid GBP100 ($150) for my new Atten 60MHz DSO's but, like your units, they came without warranty.
If you think you can justify the cost to yourself, buy one. BUT check the specs as there is little point in buying a 100MHz bandwidth DSO that has the SAME low sampling rate as a 60MHz version

Aurora