Mostly, my advertisements are done on the internet.

I do it myself so that i can be in control of the budget that will be allocated.

If you have a good reputation, any marketing method will work.
Do it yourself if you are a starter

It all depends on how much you're making and whether you can afford it or not

Thanks

It depending on yourself.
You get a professional design if you pay for it.

If you are profesional designer, of coz you can do it yourself.
If not, I don't think you designing item will as good as you pay.

Advertising is like accounting: you're better off if you know a little bit about it yourself, and know and trust whomever you're paying to handle it for you. That way, if someone's claiming that they will submit you to 300 search engines but 275 of them are tiny search engines, region-specific search engines where your target market doesn't even go, or link farms, you will know what to ask ahead of time and find out if they're going to give you quality for the money you pay, or if they're going to meet the letter of their offerings but the results will be a bit...dodgy (for lack of a better term.)

You'll also be better equipped to tell them what you want, if you know a little bit about internet advertising. This will make their lives easier, if they're ethical, because they can charge you money and do exactly what you want them to do and give you the quality results you'd expect for your money (or can competently advise you that what you want won't yield good results.)