i find a lot of their combos to be rather affordable...you just have to scroll through their offerings past the heavy 'most discounts' packages. one thing to keep in mind is that if you have a sale coupon code for one item, it can't be applied to that item if it's part of a combo. the best thing to do is sign up for their email blasts.
although most of the things exclusive to people are on the newegg mailing list show the coupon codes on the site, there are some that don't and it seemingly helps to jump at some of these offerings. the latest had some good ram that i apparently didn't get to in time at a heavily discounted rate (or maybe this was by design !)
i love newegg and genuinely find that a lot of their deals are true deals although there are certainly a number that i have seen where i momentarily feel like i've got the clock ticking against me only to find that the item in question is similarly priced elsewhere. In addition to having great deals, newegg also REALLY knows how to get you sweating and salivating...at the same time no less!
it's a great sales technique and one that amazon is somewhat responsible for with their 'hurry! only one left in stock' tags. i had a business and our merch was carried by amazon. we would frequently see some items marked with the 'hurry, only 1 left in stock'' bait tags. the reality is that they always had several units available.
so, my advice:
1. make your build. if you're like me, fantasy purchasing is its own reward even if it is a big time sucker! i'll work on alternate builds and scratch 'em out in seconds. however, if you're time is more valuable to you and you have a limited amount of it:
a) figure out the essential ingredients and make a point of pulling the trigger on those first. if the shipping is free and you have some of the cash, there's no reason not to. these are the items for which there really is no substitute - a cpu, perhaps?
b) figure out what ingredients you have greater flexibility with- computer case, maybe? - and be willing to break brand loyalty when a deal comes along. the case is the plate your fine computing meal is served on, it has a very important role of holding the guts together and just like we know we need utensils and a dish for that fab pasta, it's the pasta we pay the most attention to and not the thing it's served on...and, of course, just as many, many different plates will keep your meal from falling on the floor (to fido's delight) , a case will do much the same for your pc. though not so generic as i make out, you get the point.
c) you shouldn't feel like you've got to do it all in one fell swoop. remember, rome wasn't build in a ...i've seen pieces from a combo reemerge with virtually the same level discount (when parsed out) as an individual item deal.
d) if you are especially interested in taking advantage of combos, spend some time looking for patterns. over just a few days or, at most, weeks, you'll see certin things paired together with slight variance by brand or exact specs. the less exact you are about the parts, the easier it will be to achieve the whole and at an easy, stress free pace.
e.) finally, to come back to your original query about timing of sales, try to think like the manufacturer and the retailer.
right now is a nice time to buy stuff. summer is over, we've entered a new season AND kids are back to school. sell through is down in general right now and the retailer and manufacturer will do everything in their power to see that as much inventory is burned through as possible between now and, frankly, the end of the year. the last thing the manufacturer wants is to have a million pallets of dead stock shipped back their way because it didn't move and newegg would, of course, rather make the sale than return the merch but you can be sure that when they have to make way for the never ending supply of new stuff, they will return whatever they have to at the end of the day. Alas, i think it's fair to say that deals will be cycling through pretty regularly for awhile.