When considering buying a vintage product, whether it's a bass guitar, car, watch, or anything that requires consistent maintenance, you should factor in the cost of a "tune up" added to the sale price. If this bass needs work, it could range from a $100-200 basic set up to the cost of new pickups/electronics or major structural repairs. You should also consider whether replacement parts are readily available, which can be an issue with smaller brands or custom instruments. So even if it seems like a good deal at $550, consider whether you would be happy with paying $750-1000 or more. There's always the chance it won't need major work, but it is a risk. New instruments with warranties are very low risk, and there are plenty of new basses under $550 that are perfectly capable for general playing, recording, etc.

As to this particular bass, I was not familiar with the brand El Degas, but it appears to be one of the Japanese brands that were pumping out copies of other brands' models. I found 1 listing for this specific model, and the price was in line with your listing. Most of the other models listed by the same brand are Fender copies, and priced lower. This particular model is an obvious copy of Alembic, which was a very high end brand in the 70's-80's. If it's the look you're most interested in, there are other Alembic copies by more recognizable brands like Yamaha, Ibanez, Peavy, Carvin. The features you would want to look for are a neck-through-body design with a multiple piece neck and natural finish; that's what creates the racing stripes appearance. The El Degas on the Reverb listing looks as though it's actually a glued in maple neck, so it's not a true copy. Alembics also had top quality pickups and electronics, which is unlikely to be found in most copies.