I own a medium-traffic PHP+Mysql based site - about 100-200 daily uniques with occasional peaks of about 10.000 daily (peaks could last for a day or two or more and be 10 times higher in the future). Every visitor is very important for me, so what I'm looking for is a hosting company that actually guarantees 100% uptime and ability to maintain a reasonable response time under sudden and lengthy traffic bursts. Other requirements are not that relevant, but I need to tweak PHP.ini and be able to point many domains to my site. Shell access, cron jobs and other helpful goodies are very desirable. And preferably a company with established reputation and history. The budget is about $25, the cheaper the better. Thank you!
What are you trying to achieve here? You need hosting that will deal with your busiest periods not your average, and if your site is growing then you need to look for a host who can handle the traffic you reasonably expect. A host for 100-200 uniques per day then can be almost any host you can find. To deal with peaks of 10,000 per day then you need to tell your host what you are expecting and ask them what they recommend. If you seriously expect traffic to increase to 100,000 uniques per day, then that's what you need to plan for. Few shared hosting providers will guarantee this volume of visitors for their shared hosting, and depending upon how efficient the code is you are likely to need a relatively powerful dedicated server for these types of loads. One thing I can say, without doubt, is that if you expect 100,000 uniques to be your peak then your budget is too low by several factors. If all you can afford is $25 then you're going to have to understand that for that sort of investment you're not going to get what you say you need.
Since you need all those shell access,modified php.ini,then you need to buy a VPS. $25 can only get you low end VPS.