Based on past experience, I'd avoid lysol spray and try to find a work around rather than using any kind of disinfectant or anti-fungal spray on the shoes themselves. Really...tried these long ago and they seem to create more problems than they solve...mainly having shoes that smell like spray disinfectant rather than shoes.

Light and air circulation can be your best friend here...there is some kind of ultraviolet lamp that you put in the shoe that gives the little critters a terminal sunburn and frees you of their odor and/or infectious properties.

As you say that you're a poor student, I'd go with a jolly good airing, insoles (if they don't interfere with the fit), wool socks and a light dusting of foot powder on the feet rather than sprinkling it in the shoes. Frankly, there's a Johnson's medicated baby powder that has worked better than any commercial foot powder that I've ever found so when the need arises, I go with that.

Not to get too personal but I've gone over to wearing either wool or bamboo socks entirely and that's gone a long way to eliminating any foot perspiration or odor or fungal critters.

Best

AA

ps: In the pantheon of foot dwelling critters, beware the plantar's wart...I had one several years ago and ended up getting a quarter sized hole lasered in the bottom of my foot to eliminate it...good news is that it healed flawlessly and you an't even see a trace but it was a major PITA when it was done.