If it helps I’ve recently seen the following sell quickly on TOS:
Complete Colt M4 Carbine Lower: $550
Complete Daniel Defense Lower: $350
Complete Noveske Lower w/ quality parts: $450
You can buy a complete LMT, BCM, Rainier Arms, etc. online right now for less than $400.
What does all this tell me? Quality complete lowers are going for roughly $400 on average in this market. You may get a bit of a premium since yours is billet.
As others have said - it’s a buyers market. There are simply way too many complete lowers in the market and stripped lowers, lower parts kits, etc. are readily available online at reasonable prices.
What I would do is price out your lower at CURRENT market prices and try that amount first. You are not going to get your money back if you bought parts during the panic.
Seekins billet lower — ~$250
Umbrella corp grip — ~$20
Magpul ctr stock — ~$75
Magpul ASAP – ~$28
Bad ass ambi selector — ~$28
Milspec trigger group — ~$50
Seekins billet mag release — ~$6
TOTAL: ~$457 at current market prices
Not sure what LPK, buffer tube, spring, buffer, etc. you used so can’t price those.
I might suggest selling the Magpul CTR separately as many people might want to use a different stock.
EDIT: Two complete Seekins Billet lowers for sale on TOS. One is priced at $475 and one at $575. The $575 one has a Geisselle trigger. Just more data points to consider when pricing yours.