A message to a Puzzling User

I have decided to send a message to a fellow Puzzling User.
Solve the following clues to find out the message:

An intense request for a bargain (4)

Shorten this great community without including its leader.(2)

short commercial in the Internet, domain(3 or 4)

Most common in this language(1)

Give support to the rear end. (4)

Your chances are 50-50. If only, 5 was a letter once.. (2)

Open this not while having tea. (2)

It is a wreck. If only, it was invented 4 years later without its tail.(4)

Travel through that and criticise it (4)

After you have figured out the message, Don't you all agree with me?

The message appears to say

PLEA/SE/COM/E/BACK/SO/ON/AVIG/RAIL

all of which is pretty straightforward with the following exceptions:

SO is because SO looks like 50
AVIG is still eluding me.

EDIT: Lukas Rotter (in Sphinx's Room chat) worked out that

AVIG is rot4(WREC).

More details, in case anyone wants them:

PLEA: an intense request; in US criminal context, a "plea bargain" is what you do when the prosecutors tell you you're liable to go down for 50 years unless you agree to plead guilty to some of the charges.
SE: PSE (short for puzzling.stackexchange.com) minus its first letter.
COM: internet domain name (.com), short for "commercial"
E: commonest letter in English
BACK: means both "give support to" and "rear end"
SO: looks like 50 as in "50-50" but with 5 replaced by a similar-looking letter
ON: I confess I'm not sure exactly how this works, but something like this: it means the same as "open" in some contexts (e.g., referring to an event) and is (an anagram) of "not" without its final T ("tea"). I suspect I may be failing to understand this clue. (OP'S edit: Open means "On" in some events. Take the first letter of the first 3 words and remove "t" (Tea))
AVIG: take WRECK, remove its last letter ("tail"), advance each letter four places; you get AVIG (OP'S edit- Hence, the 4 years later thing)
RAIL: means both "travel through" (by train) and "criticise".

And I think it's fair to guess that we do pretty much all agree.

• I have a feeling it should be 'please come back to us avigrail' Nov 24 '16 at 16:58
• @BeastlyGerbil Sid confirmed in the Sphinx's Lair that "SO" is correct, and "ON" also makes perfect sense with the corresponding clue.
– user14478
Nov 24 '16 at 16:59
• I don't know about "perfect sense"; at least, I don't understand exactly how it works. I am probably just being dim. Nov 24 '16 at 17:04
• @LukasRotter Please elaborate re "ON"? I don't get it. Nov 24 '16 at 17:04
• @randal'thor Then it's just me who has a dumb theory for it: "Open this not while having tea" - You take the letter "t" (tea) from "not", and then "open" it (like a knot)... I'm a noob in cryptic clues, and just read now that every clue has to include a definition half, so I'm not sure where that is.
– user14478
Nov 24 '16 at 17:09

An intense request for a bargain (4)

PLEA - definitely an "intense request". Not sure how this fits with "bargain", but it fits together so well with the next clue ...

Shorten this great community without including its leader.(2)

PSE without its "leader" is SE.

short commercial in the Internet, domain(3 or 4)

COM: internet domains often end with .com, this being a short version of "commercial".

Most common in this language(1)

E, the commonest letter in English.

Give support to the rear end. (4)

Not sure yet ...

Your chances are 50-50. If only, 5 was a letter once.. (2)

Perhaps this is SO, 50-50 turned into letters but each letter appearing only once?

Open this not while having tea. (2)

If this is a wordplay clue, perhaps it's something like HI got by removing the T ("tea") from "this"? But I can't see how one of the remaining three letters would be removed to give a clue of length 2.

It is a wreck. If only, it was invented 4 years later without its tail.(4)

Perhaps WREC - the word "wreck" without its "tail" or final letter? Not sure about the "4 years" bit though.

Travel through that and criticise it (4)

Not sure yet ...