You can always check the price range via the GoDaddy domain valuation tool, It is not very accurate but will give you an idea.
There are other platforms as well NameBio is also a good option for domain valuation as per the current market. Also please go through the beginner's section under NamePros, a lot of information related to domain valuation is available.
Spellable LLLL.com is very high and on demand. Valued at high XXXX $ to High XXXXX $. If I am not wrong remembering, the most expensive is sold above XXXXX $, dudu.com sold 1,000,000$ on 2012. Reseller price is about 2500$
I had a couple of my 4L accepted on SH, but some were rejected. I think its always good to try and see, especially as it gives you someone elses opinion on the value as well.