recent sales in 90042 zip code in the 2nd half of 2006 and this year show sales of Single Family homes range from $290K (5678 ALDAMA ST) to upwards of the low 600K. there are some buildings that sell for more, but they're mutlifamily units. There are some duplexes (i think that's what they are) that are selling usually in the 600K range but some are even lower than that. I can't speak for the conditions of these homes but I presume that on the low end, much work may be needed to get the house up to par with whatever living standards you are looking for.
When you first asked this question, probably not but there are more and more homes in the 300 range in Highland Park. Many short sales and foreclosures so I think it's very doable but maybe a little over 300k.