Cheap Old Preamps

I'm helping a friend look for a cheap (under 100$) old (tubed would be great but not necessary) preamp, and was wondering if you all had some ideas for what to look for (probably on eBay). I've been tracking some Dynacos, but the tube ones tend to exceed our budget. Are the SS daynaco preamps just sucky? His sources include an AR/XA TT and a really old Cambridge CDP. Amplification is a 40 wpc (I think) SS McIntosh amp (model unknown). Thanks.
You should be able to buy a Linn LK1 without remote for that amount. It's a great buy, having both a MC and MM phono stage and a boatload of inputs. It uses XLR connections for everything except the phono stage which is RCA. There is a stepping sound when adjusting the volume and balance controls which is normal.
These were great preamps in their day and have a solid phono section to this day.
ps audio IV preamp. has all the bells and whistles.
ps audio quality throughout.
It includes a separate power supply,
It also has a built in MM/MC phono stage.
You can use this preamp in active or passive mode.
You will not find a better sounding preamp with a phono section for this price.
If you enjoy vinyl you will be extremely happy with this unit.
The passive mode allows you to really get a feel for what your equipment can do.
Hafler DH-101 or DH-110 are decent old preamps that could be had for under $100. The DH-101 had some problems with the push-button function switches, so you would have to check them before buying.
Try looking into the older NAD preamps as well, most have pretty good phono stages with even switchable MM/MC capability, and can be bought quite reasonably used.
And don't overlook the Apt Holman preamp.
The cream of the crop in this price range is the NAD 1020. Also look for the NAD 1155. You won't find a Linn for $100. The Apt/Holman is a truly excellent preamp but you would be lucky to get one for $100. More likely $150. They show up on ebay all the time. Avoid the solid state Dynaco PAT-4 and PAT-5 at all costs. Truly awful!
An old NAD 3020, use only the preamp section. Sounded better than the old NAD preamps and the Hafler as I recall. (Just my opinion) It also has a decent phono.
Luxman c1010 or c1000

or preamp outs of Tandberg or Luxman recievers
A lot of the old tube pres are very decent and the market price reflects that as you say. If you get a tube pre at $100 it is very likely that it will need TLC and drive the price up after purchase even if it is advertised as in "working condition". Caps, etc.. need to be replaced after XXX years. If they have been replaced it will be over your price and if they haven't you almost have to expect to do it and that will cost $$$. $100 is tough for a decent reliable tube pre on the open market.. You could bump into a garage sale special.

The Bottlehead Foreplay is a nice new pre at $150 with lots of ways to mod in the future. Foreplay
If you're afraid of the diy work you probably do not want an old <$100 tube pre as you certainly do not want to pay for service.

I don't know the SS market.

I remain,
Superphon Revelation Dual Mono or Basic
Late '80s vintage. Solid state. Simple design by Stan Warren, originally the "S" in PS Audio. I owned a DM for many years and it sounded great. Original retail on the DM was $400. Pots got scratchy after a while however. If you can find one I bet it would be well under $100.

Good luck

The 3020 mentioned above does have a good reputation. However, I think that you can get the same circuit--possibly for less--in the 1020. I've heard some people who have had a 1020 claim that when they upgraded, they had to spend over a $1000 to get something that's much better.
Thanks for all your responses. I have been keeping an eye out for a nad 1020. I know that sub 100$ is a tough range, esp. for tube gear, but we've also got a friend who's the type of guy who rebuilds stereo and recording equipment just for fun. Thanks again, and I'll be sure to check out some of your suggestions.