If you want to cut costs or do something entirely unique, look into making your own lion outfit for a fancy dress party or other special costume occasion. To help make your child feel included, try and get him involved in as much of the costume making as possible.
Buy beige jogging bottoms and a sweatshirt, preferably a hoodie. If your child is young enough, you can even buy beige footsie pyjamas for him to wear in place of the sweatshirt and jogging bottoms. Also pick up a pair of tan shoes that match the other clothes and, if possible, a pair of gloves or mittens in a similar hue. Cut small rectangular strips of black fabric and staple or sew them to the fingers, making claws.
The mane is probably the most challenging portion of the costume. You can either sew the mane on to the hoodie or make your own hood using felt or other fabric. To make a hood, measure your child's head and cut two half moon shapes, then sew them together, leaving two small strips free so you can secure the hood. Measure your child's face -- place the tape measure under the chin and loop it around over the head so it meets on the other side -- before cutting out the hood. Add Velcro to the free flaps so your child can secure the hood. Also cut half moon shapes for the ears and glue them to the top of the hood about 15 cm (6 inches) apart. Decide what you want to use for the mane. You can use wool, ribbon or fleece strips. Double the ribbon or wool over so it forms a "U" and staple the ends to the hood or hoodie. Sew or staple your ribbon, fleece or wool over the chin strap if you have made the hood yourself.
Buy some face paint, or use some old eyeliner, to paint your child's face like a lion. Paint his nose black, and then add three whiskers on each side. For the full effect, give your child a base coat of yellow paint. Smear white eye shadow on the eyelids. Using eyeliner or black face paint, start at the inner corner of the eye and trace a line over the round part of the eyelid. Put a little white on his face around his nose and mouth. Next, with black face paint, colour his nose. Make three whiskers protruding on each side. You can then accentuate his mouth with some black face paint by painting the mouth into a frown.