Treadmill, walk jog for 1 minute, then go up to 8.5 km/h. every minute increase speed by 0.5km/h. Keep this up till you can do 11 minutes and 9.4 will be ok. Do this once a week as well as other runs. You will soon notice the improvements
Saw a tv programme about 6 months ago. About 12000 army recruits, half measured and given best shoe for gait etc and other half given any pair that fit correctly. Six months later the injuries assessed and there was no difference in number and nature of foot/leg injuries. They suggest fit is the most important factor so you could be right on getting budget shoes.