The Wales international has dropped down to the Championship.
Wales' James Chester in action with Northern Ireland's Stuart Dallas
The 27-year old never managed to nail down a starting place at West Brom last season and now joins the Tony Xia revolution at Villa Park.
"The club's made a profit of nearly £2 million in a year, it's a good deal for James, it's a good deal for the club," said Pulis.
West Brom manager Tony Pulis as James Chester prepares to take a throw in
"As long as we can reinvest and get those players that we want in. We've had a great deal. Chessy's had a great deal, we've shaken hands, it's a clean cut and we move on."
Villa have now stumped up the £8 million, meaning West Brom record a tidy profit, yet there is some disappointment around the defender’s departure.
Chester enjoyed an excellent Euro 2016 tournament with Wales and fans could be forgiven for wanting to see if he could replicate that form back at the Hawthorns.
Wales' James Chester in action with Belgium's Eden Hazard
He will now have to ply his trade in the Championship and Pulis admitted that despite a strong showing in France, Chester would have still struggled for game time this season.
"He's a great lad, he had a fantastic Euros, I was out there and he had a great tournament," said the Baggies boss.
West Brom manager Tony Pulis before the match
"He's not played regular football and he wanted to play, he was desperate to play regular football. I had him in yesterday, he's been fantastic, a great lad as well. It just didn't work out and sometimes it doesn't work out."
Chester joins Tommy Elphick and Pierluigi Gollini in strengthening the Villans' backline and Tony Xia appears to be making good on his promise to rebuild the club.