you can't be a good flush cut saw!!! Prices will vary greatly, more often than not due to the steel used and/or the mfg. I've found that the big box saws and even those from places like woodcraft/rockler serve the purpose quite well and not for alot of money. I do have a Bridge City Tool Works saw that I save for those 'special' projects and it just cuts like butter!!!
When you get yours, tinker around a little bit. There is a bit of technique involved and can make a world of difference, in both ease of cut and quality of cut. As with most saws, remember to let the saw do the work and you'll be most pleased with the results..
"..... limited only by imagination"
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Skipper the Penguin