Hi there! Welcome to the subreddit. Here are some things you might want to know:
Abbreviations:
Bidding:
SB - Starting Bid
HB - Highest Bid
IA - Instant accept
Item abbreviations:
LTBS - Large Train Bow Skirt
MCN - Mood Changing Necklace
CMBR - Callmehbob ring
DV - Darling Valentina
SF/PSF - Princess Starfrost
FB - Fluttering Butterfly
DD - Dear Dollie
SE - Shadow Empress
EH - Enchanting Heirloom
etc

Values of rare items:
For halos, there's a tier list with values on the side of the subreddit.
Other rare items:
LTBS - 320k-370k
2020 Parasol - 250k-350k
OG Elegant Parasol - 350k-400k
Giant Teddy - 200k-250k
Teddy Zilla (or teddy z) - 500k-600k
MCN - 100-150k
CMBR - 500k-600k (?) irdk this one

That's it I think?
Lmk if you have any more questions!