How old is your baby? Cradle cap is normal and should go away on it's own. The special things that you can buy for cradle cap are not really effective for taking it away: they mostly just help give extra moisture to the baby's scalp. What it is mostly is that the baby lives in a water environment for 9 months, and then changes to a dry one. You might have noticed the rest of his skin peeling, especially after baths. The same thing happens on the scalp, except it is harder to rub away the dead skin with all the hair in the way.
Some of my kids had had something of a cradle cap for at least a year. As an inexpensive remedy, you can massage baby oil or mineral oil into his scalp about one hour before shampooing. While you are washing his hair, take a soft baby brush or fine toothed comb and and run it through his hair. This will remove most of the scales. Wash with a baby shampoo, rinse and gently towel dry. Be gentle and careful not to break his skin: if you comb too hard, you can give make him bleed. It's still soft baby skin!
This should minimize how bad it is, and you can do it every time you bathe him, which should be every few days. There is no need to contact a medical professional or use harmful/strong dandruff shampoos.
As for the eczema, it might be that he has an allergy to something: it could be the laundry detergent you are using or something you (if you are breastfeeding) are eating or his formula. Usually milk is the culprit. Most babies can go back to milk based products after the first year because they get over their intolerance. Usually a humidifier in his room and using baby lotion after baths and at night should help. I would recommend finding out the cause of the eczema, not just covering it up with lotions.
If you think he is in pretty bad shape, you can ask your pediatrician if he recommends a cortisone treatment especially made for your baby's specific needs.
