Well i have Copper and Yayoi are Uncommon, but are very good cards if you are going by skill and not just rarity. I could give both and common cards you are missing for 50 creds, not a bad deal.
I could add a rare card after the trade, i would just need to sell some cards first then buy it.
Sorry, but i didnt even buy my own credits. i did the asme thing you did. dont worry youll get there u just need to find the right person with money. it will be easier for someone to buy credits for you if you have a collectors card. thats wat i did.