I think if you are looking for an entry level bike along the same quality of your MTB, you'd likely spend around 4-$500 for something new. The problem is, bikes below a certain level of quality are great for neighborhood rides with the family and the occasional 10 or 20 mile journey but if you seriously get into riding, the stresses you will put on them will cause them to wear out and break down pretty quick. This is why the generally accepted range for entry level road bike around here is usually over $700 and closer to 8 and 9. Simply because bikes at this level are high enough quality to last for a decent amount of time.

55/Rad