got some older 550/551 mags and not sure what they are worth.

All are factory mags. I have 2 30's, 6 20's and 1 5rd.

any help would be appreciated

You could get $75 a peice right now I bet.

i have some posted in the EE for 75 and they are not moving so, i would say try 50

I'll buy them at 40 all day long. They seem to be "immune" to this gunflation, since it's a pretty niche market.

Ya I have seen them priced at $40 all the way to $120 at cogunsales.com. Pardon my ignorance but why such the variance in price?

really there are not many swiss style lowers out there. while i like the look of my swiss style lower and mags, its purely cosmetic, i still have my orginal lower so i can swap back to AR mags at will, but having a lower/rifle that takes 12 dollar mags is far more apealing than one that takes 40 dollar mags that most people have never seen

I was considering a 551-A1 SBR, but I have decided to hold off.  If the current mania blows over and we get through the next cycle without a new AWB, I'll look into it.  However, I am not going to lay down the money for a 551-A1 that takes $40 (minimum) magazines, of which I don't have a stockpile, only to have the new magazines and/or the rifle banned.  I am pretty confident we can avoid a new AWB in 2013, the votes shouldn't be there for it, but one never can tell.

Just switched my 556 sbr to a 551 sbr.  Was worried about the mag mania buying but managed to get 6 from sig, should be 7 but they forgot one with my lower

In early December, 2012, just before all of the current panic buying madness, I purchased from Top Gun Supply four of these SIG 556-A1 type magazines for $49.95 each.  Top Gun Supply is now – like everybody else it seems – out of stock.  On the Top Gun Supply website, it is interesting to note the “Hi-Cap Restrictions Apply” warning.  It is often forgotten that already in many jurisdictions in this country, so called “high-capacity” magazines are already banned!

Link to Top Gun SUG 550 – 551 – 552 – 556-A1 magazines: http://www.topgunsupply.com/_search.php?page=1&q=SIG+550+magazines

Back in July, 2012, when I purchased my SIG 556-A1 lower directly from SIG, I also purchased three 556-A1 type magazines for $39.95 (a sale’s price).

So I would say that approximately $50 each would be a fair price.  I hate to suggest a higher price, but maybe $60 each.  

I just got six 30 rounders from Sig and they were $42 each plus a discount of 20%. This was last week.    $50 is a fair price.