I'm no expert on this, just my observations during a learn curve before Internet betting.
At the races, in the ring, I observed the layout.
The bookies, the tote screens, the people, the stables, the rounding yard and the track.

The bookie's stalls and the tote screen's positioning favors the bookies. They can watch the screen while they work their boards.
When I wanted to go observe the horses it was a long walk from the betting ring, and a long walk back to the betting ring to see the prices on display.
So I could not go see the horse, make my assumptions then go back and study the "game" at the ring.
It was painful, drank lots of water, and of course ya have to do what ya have to do, then all that effort and it may lose !
But I got an idea of what's going on.
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One day, I was losing, every Form type selection just did not win.
On the tote screen on this particular fleeting moment, my eye caught something, a plunge, a horse went from 7.50 down to 6 then back up to 7. later it graduated to 8's and 9's ~.
One bookie saw it to, he put his price up to 9.50, and others followed suit then they started playing around with the prices on the 2 favorites, around the 25/10 and 3's.
I waited in "hiding" amongst the crowd, observing.
The bookie moves it up from 7/1 to 10/1 and I put on my last $100 betting money for the day @ about 30 seconds before the race was to start.
This other punter pushed and shoved, nearly fell over, betted on the same horse, he saw it to. I think he was watching me cos he rushed in straight after I put my bet on.
It won.

Ok, so what was the probable cause of this win ?
The 2" favorites" were on the inner barrier, it was a very wet track and it was late race. Track had a mud patch near the rail on the straight, the same mud patch was there from race 2 of that venue earlier, but I did not pay much attention to it.
The horse that won was out on the dry section of the track, barrier 7.
It was it's 1st race after a spell, it came 2nd before the spell.
The bookies tried to "scare off" a plunge on the obvious, observed by this subtle plunge on the screen.
It was luck, right place at the right time, the "fleeting moment".
As a analytical sense it was not luck,it was a calculated risk right there and then, the catalyst was the mud patch on the inner part of the track.

Nothing can stuff up the bookies in the long run ( except maybe dwindling crowds), it was one race only a few got to "see" it. Hundreds more in the crowd that day were betting on those 2 other favorites trying to go around the mud patch. This took "time", while the 10/1 runner eased through clear of the other horses.
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If you want quality non web page real-time prices, I suggest you try a subscription data service.
http://www1.subscriptiondata.com/
( but they won't show you the mud patches )
If your punting can sustain this subscription cost, plus programmer developer costs and maintenance, then I think this is the way to go.
I think, not sure, but I think they got the sole Australian rights to TAB prices nationally,
then it goes out from there to the web pages,pubs, clubs and I have heard of one punter has a dedicated TAB/Sports "man cave" out the back yard with a couple of dedicated and loyal rottweilers

This may be the only way to go for some private home use punters.
BUT, ya have to prove to yourself with real results before converting from free web scraping methods to a payed service if it will pay for itself from the winning bets, like any business...,from 12 Months Subscription $780.00
But