Start with an AEG before you move into GBBRs. VFC, KWA produces amazing AEGs. Sometimes, you have to put out cash for quality so you don't end up with a quantity of garbage.
Once you have your AEG, Get 5 mid-capacity magazines. MAG brand produces amazing mid-cap mags at a relatively low price.
Now that you have your magazines you definitely need somewhere to put your mags inside. You need gear. This is completely up to the operator and the operation. There is no best loud out. Just plan it, and try it before you buy it.
Going back, the AEG provides a reliable back up to your GBBR (if you decide to purchase) if it fails during game. If you're not up to afford a KWA or VFC, King arms makes a great full metal m4 with good internals at a reasonable price.
Good luck, and have a great eye-pro.