Wide gap.
One more instance that shows why, when people do all-grain, they should have their own mill. I know it's not that easy to budget for some, depending on where they are in their life cycle (my kids are grown, e.g.), but it's one of the things that can result in a major leap forward in brewing (others being things like fermentation temp control, water composition, etc.).
That is, when you have your own mill, YOU control the crush, not MoreBeer, no the LHBS....you.
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I think the Cereal Killer mill is a great price point--very good performance, capacity, and the price ($99 delivered) makes for a great price/quality/performance mill. I know someone will come on here and advocate for a Corona, but a 2-roller mill, IMO, is far superior, if you value your time and convenience.
Further, if you can buy malt in bulk, you can pay the thing off in relatively short time, meaning from then on you save money. A lot of LHBS will sell you malt by the sack; you can also get it online, and there are group buys and such. I'm fortunate in that I can get 55# sacks of Maris Otter for about $1/pound from Ritebrew; they have 2-row for 74 cents/pound in 50# sacks.
I have a friend who goes past Ritebrew on an occasional basis; he brings stuff back for me, so no shipping costs. I'm lucky that way, but there are ways to cut your grain costs down significantly.
So....do the math, see you can afford one through the savings from buying in bulk. I know that you not only have the cost of the malt up front as well as the mill.....but if you can, do it. It'll save you money in the long run, and the control you can exert over the process is considerable.
You can get fancy in how you store it or you can use garbage bags. Most malt sits in sacks in some warehouse for months on end, so provided you use it up in a relatively timely fashion....not the most crucial element of storing grain.
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I haven't done a lot of business with MoreBeer lately, though I bought a lot from them when I started brewing. I see these things occasionally about their performance and it seems it's slipped. Every once in a while I'll get the email about $25 off of a $150 order, which isn't a bad deal with the free shipping. Sadly, they don't include the Torpedo kegs in the eligible products.
Have they been bought out by someone in the BMC crowd?