This is when someone who cannot spell writes something, checks back and realises it was mispelt and types (sp)} after it so they don't look as uneducated.
Text slang popularized by the instant messaging age, used to ask if the spelling of a preceding word is correct. Seen more often in discussion forums where grammar is emphasized.
Short for "Starting Price". Originally a gambling term for the odds that would pay-out on horse races. In modern usage it is a generic term used when one wishes to receive a clear and concise response. Similar to an "executive summary". Used in the UK in the same way as "bottom line" in the USA.