Many beginners will start riding on a well-priced frame produced by Onza; these frames are based in a low price range and have a well proportioned geo. Unless you've had previous experience in building a bike, personally, I would recommend you purchase a full build Onza, as these are cheap and very reliable. I wouldn't recommend purchasing a bike of high price, as being a beginner you are likely to damage the down tube with prominent scratches and dents. A recent brand of trials-biking has come onto the scene, with 'Because' frames, these can be found on www.tartybikes.com, click here to direct you to this website. EBay is a great place to purchase second hand bikes and frames, so it would be handy to check here. On this forum is a sub-section named 'for sale', where, you will be able to purchase any frames you like the look of from other members, along with the 'wanted' section, where you will be able to post a new topic, requesting any frame or bike parts you need and want once validated. Hope I’ve been some help.