php code for finding buzz words

[naresh.vil]

$str = "Save $20 on purchases over $250 from Goldspeed.com save on"

from the above how to get Save $20 ?(Save $20it may any place of a string)

like the above

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  i wnt to find somany word like "Save $XX

Save up to $XX

up to $XX

 

If there are two $XX with the same format then chose bigger number

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XX% to XX%

XX% off

From $XXX

For just $XXXX

only $XXXX

for $XXXX

For $XXX

only for $XXXX

Starting at $XXXXX

Starting $XXXXX

for $XXXX

$XX and up

$XXX Each

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Coupon Code: XXXXX (only one word)

Coupon Code XXXXX (only one word)

Promotion code: XXXXXXX (only one word)

Promotion code XXXXXXX (only one word)

 

If you don’t find top 4 then search for this one

 

Code XXX (only one word)

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plese help for findind special character dynamically