I had never interested in mixed type domains.
Last year, when was the big buyout of short and numeric domains I only watched the process, now I am watching the drop...
You maybe know all 4 symbols .net .coms, even other extensions were totally bought, mostly by Chinese people.
Out of curiousity, I made a custom search of Godaddy auctions - pattern LLLN.com.
Here is what I found.
4,000 are curently on GD auctions.
Some have offers - they are aged and having good pattern like xxx, btc, htm, php.
There are many at closeouts and one can buy for $5-$11 but probably no one will and they will drop because are random symbols.
There are also domains on expiring auctions and only one has a $10 bid - psm1.com - it has traffic and GD valuation above $1,000 (there is a thread about that new feature of GD)
The rest ones are listed with makeoffer/buynow option between $xxx - $xxxxx.
I found out that many of them had actually expired and available, like
fsn8.com $19,000
spf5.com $9,500
dtv4.com $8,888
tmx5.com $5,000
tmx9.com $5,000
dnp4.com $1,000
spx3.com $900
kmv6.com $850
xjr6.com $850
kcx8.com $800
dwk4.com $800
flx0.com $800
xnx2.com $788
wwk2.com $750
gtt9.com $588
and many more.
Took a look at registered ones from that list - there are some in redemption/pending delete stage, others will expire soon an probably will be deleted.
Most of them, logically are registered in last year. (I will attach a part of the csv file to take a look who and when registered them, which domains were renewed etc.)
I think it is risky to invest in such type of domains, especially for newbies like you and me.
Of cource, if I found a domain like phpN, betN, sqlN, ftpN and similar hight valued 3-letter words+number, I will register it.
The true is there are no such available words - all are taken long time ago, renewed and no chance to drop soon.
Will attach this file too - may see there are several words like owl0 or lov9 that were not renewed but the others strong words are taken forever