You can buy parts like these much more cheaply secondhand, and put cars back on the road for far less than it would cost to do a pukka repair using new, genuine parts.
The catch is that you have no way of knowing the provenance of the parts you're using. That ebay axle could turn out to be no better, or even worse, than the one that needs replacing. Most body parts on ebay will be from salvage cars and you've no way of knowing what stresses they were subject to in the previous accident.
At the end of the day, you pays your money and you makes your choice.
My concern would be that a shunt sufficient to bend both the front & back axles could have put the chassis out of true, and if that's happened it'll be wearing tyres prematurely for the rest of its life. Sometimes the best thing you can do after a prang is to find the cheapest way to get rid & move on to another car. My own experience has been that cars needing any but the most superficial of repairs have never been quite the same again.
Buying a repaired accident damaged car, whether recorded or otherwise, is IMO a risk not worth taking and I would sooner walk away from what might be a perfectly good car than take the chance of ending up with a lemon.